honestly, you wont get more than 145-ish unless you rebuild your motor, or go with a cheap turbo kit. header+exhaust and an intake, and you are realistically looking at 140 or so at the crank. if you can get an mp3 ecu, that will get you to 135hp with no other mods. of course, all these numbers assume that your engine is still running at peak factory efficiencies.
i currently have an injen intake ($130), a magnaflow exhaust ($375), a header ($125), and the MP3 ecu ($250) and, according to my iphone, i'm pushing 145-150hp. thats probably on the high side, too. all that for at least $700. considering you could build a turbo kit from used parts for ~$1200 or so, the way i went is not really the cheapest way to add power.