Dude...
DUDE.
What are you waiting for?
The 4S is a HUGE leap from the 3GS. The 5 will be... no words to describe the leap from the 3GS. Mindblowing is the only word I can come up with but it'll be more than that.
You pay more than $50 per month for your phone plan right? Might as well ditch the 3GS and at least get a 4S. I would definitely get the 5 if I were you though.
You are good at this hyping