The Spyder software as an option to "recal" your monitor, as opposed to going through the full calibration again. I'm really not sure what the difference is, but can we use that, or do you recommend going through the full calibration again?
Oh, and I also have very dim light where I edit, so I have the trifecta for bad calibration: Miller's lab, cheap monitor, and dim light. I have to invest in a lamp and some daylight-balanced bulbs. It is a windowless room, so I have that going for me.