Earlier on the OP said:
On the computer page,it says drive C has 110GB free of 288GB.
That means there's 178GB of total data between Windows, installed programs, pagefile, possibly hibernation file, user and system data, and personal files.
A rough estimate, I'd say there could be at least 130GB of personal data involved.
It would be good to have someone take a look and see what's what more exactly, data wise.
EDIT: Forgot to make my point... With a little squeezing those 130GB of personal files
could be copied to a newly created 3rd partition, there's 110GB of free space. I know that involves installing Minitool or something, and there's a chance good files are hiding in the deleted area. Only the OP can know what files are still useful and are worth retaining. Maybe it's way less than 130GB.
$50-60 for a 1TB internal drive (if the OP's 2006 system supports SATA) is the best deal around, brand new. The savings become negative or marginal for smaller drives, like 320GB or 500GB.
From what I remember, if the system supports 320GB (> 137GB barrier) it should support up to 2TB. So 1TB should be working.