i don't think you could split a bootable cd into 2 CDs and to be honest i wouldn't take the risk splitingthe Window ISO, its hard enough getting it to install sometimes with having to mess with 2 CDs. .
you cant even take the HD out unless you have SCSI ports and i don't think theres an IDE slot on the 2650s motherboard.
seems like your at a loss mate, have a poke over eBay, DVD drives are dirt cheap these day,your bound to get one for < £10.
EDIT: i just had a quick poke on Goole Shopping as ebay is blocked from my office but i found a HP DVD drive slim line for £9.99 -
ebay link if it works for you: