Hi. My mom is an elementary teacher who knows a few people in your profession, so i feel like i have some knowledge over the topic.
They were underpaid here too, used to earn quite less than the average population. My mom works in a small town and up until 2 years ago she earned barely over 800 euros per month. But the workers protested and striked for several months in breaks through recent years nation-wide. After numerous attempts through strike, their average wage became around (8 000 HRK/cca 1 080 euros). There are some rumours over their wages getting even bigger.
You should generally search for a job in Zagreb. It's by far the most job-providing place in the country, especially in this field. I can't say with full confidence regarding most of the northern parts of the country, but in the south where i live, finding job as a teacher is damn near impossible if you don't have a ''guy'' to fix it for you. If you don't have a guy, you will most likely be either a substitute teacher or you won't work for over a year or two. Lots of nepotism and political shadow play. On the job adverts, in the southern Croatia, every time i sniff around for a job of my own, and i do that like every half a year, i see maybe 3 or 4 places looking for a teacher.
There are many sites, such as:
burzarada.hzz.hr (national employment institute)
Good luck!