WEP is insecure. You shouldn't use it. Use WPA2 instead.

Instead of going with NDISWrappr I suggest you buy a (second hand) alternative instead. Its much more pleasant to use a native driver you stick in and it Just Works. You'll have to open your laptop though. But that shouldn't be too hard. mini PCI Express on eBay. Example as of now: third hit is someone auctioning IWL3945 for 18 USD. Is a good card with good signal strength. Its even sold for 10 USD too. More refined search. I highly recommend these Intel cards because they Just Work (tm) on Windows and Linux (Mac OS X is a different story).

Alternatively, you can pick a USB stick WLAN and plug this in. These are pretty cheap. ZD1211 for between 8 - 10 USD.