The fact that you're short on cash makes the rig upgrade MORE important than any relatively minor improvement in tone you can get from a pedal. I'm lucky that I had bank to buy a real rig the minute I was offered paying gigs ( after showing up with a practice amp to unpaid gigs and getting blisters ) so I know where you are and I know where you need to be. The short path to get there is blindingly obvious, backed up by almost everyone else in this thread.
Bottle the GAS, save a little, you can pick up an older Peavey combo that will rock your socks off for only an extra $50.
Bottle the GAS, save a little, you can pick up an older Peavey combo that will rock your socks off for only an extra $50.