You have yourself in a corner here my friend. Looks as if you have 175 Gig. of something and only 10 gig free!
The first piece of advice I would give you is don't try to keep anymore data. You are very close to not working now.
You really only have two rational choices here. The first would be to off load all, or most, of your data to some other storage device, hard drive, stack of dvd, etc. The other is to deep six, (throw away), a very large chunk of your data, if that is practical.
Do yourself a favor and when you repartition make a relatively small / partition, about 12 Gig., and put all your data on a separate partition, which you can then mount in your /home directory. Keeping your data on a dedicated partition has some very big benefits when it comes time to upgrade.
Take a look at my posts in the thread below.viewtopic.php?f=90&t=11872&start=0