The vast majority of AR parts are interchangeable. The only difference might be some parts don't interchange with others (for example, while any AR can have a milspec or a commerical sized receiver extension, you need to make sure you put the right sized stock on the extension that you do have).
Things like handguards, pistol grips, magazines, optics, etc., all that interchanges so long as it fits (you won't fit a rifle length handguard on a carbine length gas system).
I'm not all that familiar with your exact model. I'm guessing it has an A2 style fixed stock; in that case just buy your stock and receiver extension as a kit (you may need a heavier buffer, but that depends on how well it functions once you get it put back together) so you have parts that fit. Be sure to be careful when taking off the stock- there's a spring and detent held on by the stock; if you lose those, the safety won't stay put. As for magazines, any AR mag should work. If you want to try the popular Magpul Pmag, I'd start with buying one to make sure they drop free from your magwell (sometimes they do, sometimes they don't). If you go for regular metal GI style mags, feel free to stock up, but don't spend more than $20/each.
