In that case, what I would do is this. As you have two hard drives, leave the boot drive (C:) alone. Temporarily disconnect one of your CD drives and connect your new hard drive in its place and copy everything from the second drive to the new one and then remove the second 10GB drive. I wouldn't have just one hard drive in case it fails, then you have lost everything.
Alternatively, some CD writing software allows you to make a hard drive image, if you have this facility then you could make an image of your C: drive and copy it back to the new drive, this would involve temporarily connecting the new drive in place of a CD-ROM as above. I've never tried this, so don't know how successful this would be.
Or, you could buy disk cloning software such as Powerquest Drive Image Pro or Norton Ghost, however as you are not likely to use them much it may not be worth the money.