i assume you just bought the bike. So ill give you my 3 cents.
if you're loaded with cash, i would go for a bottom-end overhaul. 140 Italkit with 0111 Jollymoto belly equivalent and Zeeltronic PDCI12 CDI to adjust the valve timing and a 34mm carb. that should grant you a good amount of power & torque by bolting it on.
if you are on a budget. bottom-end overhaul, refurbish your current block (I hope is an original Aprilia) and deck it or buy a pre-cut cylinder head to get squish approximately 1mm. the rest can go standard and you still can get away with pretty decent power. you will be surprised by just refreshing your old parts to "new" can do a lot to your bike.
but overall getting the carb tuning right is the icing on the cake.