I spent a little bit working on this build for you. I'm a fellow kiwi, so hopefully I have all the prices to some shape or form of accuracy.

Because of the limitations on your budget ($1000) and your need for everything to be included - like the monitor, which adds quite a lot of money onto the total price - I've gone quite a bit ($150) over though. I feel that it'd be difficult for you to find more functional parts for cheaper prices, especially in New Zealand - saving another $30 in the CPU department might give you half the performance etc. Let's discuss what you want to cut down on.

You specified that you wanted to be able to upgrade in the future, which really limits you on how low price on components you can buy now - things like the motherboard and PSU need to be fairly decent in order for you to not have to replace them next time you upgrade.

It does not include the OS. You could buy a cheaper motherboard that would work with the parts, but since you specified that you want to be able to overclock down the line, that's the cheapest that you should go. I can help you with putting together a different list if you can't get hold of a bootable disk/drive with Windows on it, but I'll post this one anyway.

PCPartPicker part list / Price breakdown by merchant

CPU: The G3258 is a decent overclockable CPU - even without an aftermarket cooler, you should be able to get a decently high stable clock on it. It is a dual-core though, and might struggle a little bit in GTA V and The Witcher 3. Also, it might lag behind a little bit in Photoshop - shouldn't be hit too hard though. However, it's a CPU on Intel's LGA1150 socket, so you have a strong upgrade path through the i5s and i7s.

CPU Cooler: Because you're trying to make a super budget build, I didn't feel that you needed an aftermarket cooler, and the stock one should be fine until you want to upgrade.

Motherboard: This board lets you overclock as much as you want, and supports another set of 2x4GB RAM in the future if you feel that you need it.

RAM: 8GB of 1600MHz RAM should be more than enough for right now - you can always buy another kit in the future.

Storage: The budget that you have doesn't really allow for an SSD to be incorporated into this build, so I chose the cheapest 1TB HDD that I could find.

GPU: Now, this was a difficult decision. There are a few viable cards at or around this price point - around the same price and performance as the GTX 750 Ti is the R7 260X, the R9 270, and the GTX 760, the 270 and 760 being a little bit more pricey. I didn't feel that the performance boost of the 760 or 270 justified the extra $40 required right now, and the 260X performs slightly inferiorly to the 750 Ti. Other options were the much (+$80) more pricey GTX 960 and R9 285 or R9 280X - however, that would put you waaaay over budget so I'd recommend that your graphics upgrade when you feel you need it should be to an R9 290 or GTX 970 in a few years time. I don't have experience with the performance of the 750 Ti - maybe it'll hold up fine. The CPU will probably be the first bottleneck, so upgrade that first - you probably won't need to for a couple of years.

Case: This is a fairly budget, black-themed case. You also have the option of the slightly more pricey and slightly higher temps of the NZXT H230 - however it has a glossy finish, which I'm not sure you'd like, and it is slightly more expensive.

Power Supply: The CX600M will be more than enough for the parts now, but will give you some headroom for upgrades in the future. It's not the most high-grade 600W PSU, but the best you will get at this price point.

Optical Drive: If you have access to a different computer (ie a laptop), you can just make a bootable USB drive to install Windows, so you won't need an optical drive.

OS: Let's discuss this.

Monitor: The AOC E2460SD is a pretty standard 24" 1080p 60Hz monitor - I actually have it, and it's served me well so far.

Sound Card: You don't need one.

Wireless Adaptor: If it's possible, route an ethernet cable to your computer for a way superior connection. If not, you can probably find a $5 wireless dongle on TradeMe.

Keyboard: The K100 is a fairly standard PS/2 keyboard for a good price ($25 inc shipping), but if you can look in a local store for cheap keyboards, that would be ideal.

Mouse: The two mice I have listed are solid gaming mice for a good price (~$45). The G402 is a common choice, and the Naos 3200 seems to be a good mouse as well. If you don't want a gaming mouse, try to (once again) look in a local store for corded optical mice for cheap.

Audio: I'm not sure what you want in this regard, so I've left it open for discussion.

All this looks good on paper, although it's over budget. Please either PM me or comment here to talk about prices and parts further, as I know you won't want to spend so much more on a computer. If you go to the pcpartpicker link at the top of the parts list, I have a bunch of non-priced parts - these are links to the pages where I found the prices that I did. Use pricespy.co.nz to double and triple check my prices are right.