It sounds like your X and Y calibrations are off. In the firmware, there are variables stored for how many stepper pulses equal how many mm of movement. Not sure how to write new values in there, on some machines like our Lulzbots you can do it from the front panel, on others you have to have special software tools to write new calibration values.

The temperature issue is probably unrelated. I had that problem on one of our Makerbots after the insulating tape was torn off during a failed build. Getting replacement insulation from Makerbot support fixed that problem.