I've not done it myself, but Windows 7 supports this. Go to the Network and Sharing Center, click on Setup a new connection or network and the last option on the window that pops up is setup a wireless ad-hoc network.
You should be able to run that on both systems and get them to connect.
Edit after reading the real problem
Connect them with an Ethernet cable. The ad-hoc may be faster, but that that much faster (unless ad-hoc will get you 802.11n and the router is 802.11g). The best you could hope for is half-a-day If at least one of the laptops has gigabit ethernet, then you don't even need a cross-over cable, it will auto-detect.