Buy B18C GSR block,
Plonk block into your B16A head setup.
Cost, probably about 3-4K, depending on how much you get the parts for.
You should be getting more hp out of it, but it's only as powerful as you're willing to spend. The cams, intake etc. can come later if you want more power.
B16A is quite pitiful in terms of torque, so just make sure you remember that, no matter what mods you do, there's simply no replacement for displacement.
B16A can be made powerful like the B16B type R, but depending on the stuff you have on your car.. might be cheaper to simply buy a type R engine, but if you're buying a type R engine, might as well go for the 1.8 version.. :P
But a properly modded B16A vs. a properly modded B16B.. B16A will makan asap.. :P