I did a search for your difficult to find BCD on eBay and I can find the rings you're looking for, but they're about $50 USD and up per ring.

I also did a search for 170mm cranksets (searched "170 crankset") and I found many, including rings, for less than $50.

So if your bottom bracket is square taper it may be cost effective to swap the whole kitten kaboodle. As for compatibility, without knowing what derailleur you're using and its associated chain wrap I can't say if the selected replacement will work or not. Frankly, I suspect you'll be fine with most offerings so long as you keep the difference in chainrings similar to stock, so a difference of 10 teeth. Plus, you can alter the aesthetics while you're at it, which is fun.

Posting pictures motivates all sorts of answers around here. Lots of bikes are foreign or weird, but with a quick glance these C&V guys can deduce all sorts of information =) I come here mostly to see the interesting solutions to peoples' atypical problems. Good luck with yours =)