I dont think turbo would be worth it for what your looking for. there is alot to building a a turbo setup and doing it right. stuff adds up fast. Fuel pump,injectors,regulator,exhaust,wastegate,blow off vavle, fiding turbos.
I think you would have a hard time buidling a turbo setup for 3k.
Me personally would put
Cam and Valve springs
and tune it. If really wanted to get some decent heads for it or do a little work to what you have.
should have no problem picking up a extra 100hp with those mods.