I would just drop the $66.95 (you might find one for less) than try to rig a desktop power supply to power a laptop. Even if you could do it the time it would take to rig something up would probably be around the same price as buying a adapter unless you value your time cheap.
http://www.theeldergeek.com/repair_ie6.htm
Sadly, IE is one of the hardest to repair/reinstall (it will work sometimes and then not work) this is the problem with being deeply integrated with the OS.
Read
http://compnetworking.about.com/cs/wireless80211/a/aa80211standard.htm
http://news.com.com/FAQ+Wi-Fi+alphabet+soup/2100-1041_3-5669837.html
They should give some quick answers.
I think this would be easier if you would to post your motherboard if known (or the system brand and model) and some system specs.
Price range and what you are going to do with this upgrade might also help.