if you have the space in your case, it is really easy to add another hdd to your pc. set the jumper to CS, put it in your case, connect the IDE or SATA cable, and the molex and fire it up...
Connect the new drive in the second port. Alos find an extra power cord that fits and plug that in.
You will have to check the drve manuals to see about jumper settings. The old drive needs to be set to master and the new one should be slave.
After that, you can go into Administrators tools in the control panel and then Computer Management then Disk Management. You can partition the new drive any way you like.