I just bought a pregnant guppy!? PLEASE THIS IS URGENT! I NEED FISH ADVICE, QUICK!!?

I now own a pregnant female tiger guppy as of just under an hour ago. She's still in her bag because I have a tad bit of a problem. I currently own a 20 gallon fish tank with a single comet goldfish in it and a 1.5 gallon with nothing in it. I just filled the 1.5 gallon with conditioned water and I'm still waiting for the water to lower to room temp. What should I do? Should I put her in with my comet [filtered tank] or wait until the water gets to room temp and put her in the 1.5 gallon with NO CURRENT FILTER? I'll be able to buy a filter for the 1.5 gallon tomorrow but for today I am out of luck [it's too late and my 'rents don't want to go to the pet store for a second time in one day]. Also, can she wait until tomorrow for food? I only have goldfish food right now. And do they absolutely NEED a heater? I have one, but it won't really fit all that well in the 1.5 gallon. And also, in what ways do I treat a prego female guppy differently then a regular guppy? Please no haters right now, I'm in a crisis! I really do care for animals! I just have some questions! ALL ANSWERS APPRECIATED. Thanks Yahoo!{;