This tutorial shows you how to partition your C drive without affecting the recovery partition. Partition Wizard : Use the Bootable CD
It's a free download to create a bootable CD so once you've done it you insert the disc into your optical drive and boot into to repartition your drive.
As for the recovery drive, it does exactly what it says on the tin - it allows you to recover your computer to its factory state i.e. how it was when you first bought the computer.
One thing I would strongly advise, and that is to create a set of recovery discs before you do anything else so that you'll be able to recover your system should the recovery partition get corrupted.
Your computer documentation should show how to recover your system and how to create the recovery discs. One point to remember, recovery from discs takes a lot longer than using the recovery partition. You also need to remember that if you do carry out a factory restore, any data you haven't backed up and any partitions you have created would be wiped.