I have to say that the short answer to your question is "NO" you are not going to squeeze much HP from the beast without spending good chunks of hard earned money.
But, it all depends on what your budget is.
The 3xK&N will run you around $120.00 and can easily be done yourself. But the Tunebody to richen up the fuel is going to be another $300.00 and should probably be done. To really benefit from the freer intake, you'll need new less restrictive pipes to loosen up the exhaust, which will run you from $600 to $1500.
Do all that and you are looking at about a 10-12% gain. Noteworthy, but not life changing, and not exactly cheap either. Start talking cams and blowers, and now you are looking at major expenses.