Just be aware that there may be a hidden restore partition on the drive and it may well sit between the two partitions that you already can see. If this is the case then I would suggest downloading one of the free partition managers such as Easeus Partition Manager link text
1: http://www.partition-tool.com/?gclid=CLf7rYWavagCFUFC4QodKQzGAg that will allow you to move the hidden partition to the end of the drive. You can then change the other partitions to suit yourself. Just remember that it is very advisable to back-up all the files before doing anything with the partitions.