New 1990 Storm Owner, with one problem...

Hey, I am the proud new owner of a 1990 Geo Storm GSi 1.6L DOHC, and I love the car, but I have a few questions/problems.

First is, my temperature gauge never reads higher than just above 1/2 way to hot, but it overheats...
My basic knowledge and that of my father, allong wiht checking coolant levels when cold and warm, checking for bubbles ect, tells me its BOTH the thermostat AND the temp sensor, is that possible, and how can I test this?

Second, the Radiator fans never turn on. I checked all the fuses, and they all look good, but I don't know how to/where to get the relay checked. Could it be the temperature sensor, or is it more likely wiring or the relay?

And finally, when I bought the car, it had NO power steering, and upon further inspection, it turned out there was no power steering fluid, but now that I added it, Its hemorrhaging fluid. It looks liek its leaking just behind the transaxel, on the drivers side, but I cant see where without getting under it, and Im not equiped to do so ATM, is it common for them to leak back there, is there a fitting or rubber section back there thats causing this?

Any info is greatly appretiated.

I found the source of two of the problems, turns out the connector for the temp sensor was disconnected, and broken so it wouldn't stay plugged in. A little electrical tape fixed that for now, and now my radiator fans work, as well as my temp gauge. second thing I found was there was NO thermostat, literally, it was missing, so one trip to checker and $8 later, I have no more heat problems.

But now I have a new problem, randomly the car will decide to Idle low, like 500RPM or lower, want to die, and then when I hit the gas, it seems liek it doesn't know how hard I'm pressing it, and it revs up to ~3k RPM, and then bogs down like its flooded. I don't know how to test a sensor, or even where to begin, because it seems like its a mix of a TPS and something else to me, so any help is appreciated.