Pop eye... BAH! need some advice.

Due to my stupidity and leaving the window in my room open I had to do a population check as my water temp was WAY to low. It was at 70 degrees vs. my normal 75-80. It's been down to 35 tonight outside. I've lost a neon as far as I could make out of the corpse and a white cloud which I can't find any where. I stripped the tank down and did a fast check while I did a much needed water change after a failed feeding experiment with brockly. Anyways one of my neons apears to have pop eye *sigh*. I can't quarenty him as I HAVE YET to get that **** 10 gallon up :rant: so I'm looking at putting him down. I'm heading out to Wal Mart as it's 5:30 am and they're the only place I can get anything to treat the tank in case it spreads. I did a search here and found afew threads that said Maracyn 2 can treat it. I'm hoping to stop it's spread if they have it other wise I have to wait until monday to get it from the GOOD fish store in town.
I need a better heater as well. My room gets way to cold in the winter I'm adding a cheap All Glass heater in as a secoundary heater once I get back but I need to know a good brand/model of heater to order online or buy locally. I'm hoping the secound heater helps keep down the recent temp swings I've had that most likely lead to this. Well other then the stupid brockily thing I did. I'm sure that helped. (and I know not how to spell that vegi LOL)
-Neo Sithlord

Well it's done the sick neon got put to sleep with a little vodka. It's the most humane way I've read to put a fish to sleep. I had no where else to put him aside from the main tank or a small betta bowl I bought in my less informed days :sad . All I could find at Wal Mart was Mela Fix so I picked some up and treated the tank. Between having to kill one of my fish and having to run out to get the medicine. I wasn't able to take the carbon out of my filter tonight but I figure it should be ok until tommarrow night when I get out of work. At least I started treatment to be safe. Then again I count my self lucky that I live in Wisconsin since Mela Fix is known to cause cancer and reproductive disorders in the state of California *grin* (sorry I have an odd sence of humor).
-Neo Sithlord
*on a side note* The neon didn't seem to be to distressed. 25% Voldka was sugested when I was debating putting my first betta down... I wish I would have done that back then. He would have suffered so much less then he did. I still feel bad that this seemed like the only option but some times we have to kill the ones we love.