Although you might think it as a pain in the ass, it really only takes 2 minutes to change your manually config wireless adapter back to the default, obtain an ip address and dns automatically.
If you want a permanent solution, do as the fellow on here did: buy an alfa
500mw (.5watts) usb high powered usb wifi unit which is approx 50.00 on ebay.
Your signal will go from low to very good or excellent. The key is the realtek
rtl8187 chip on it, that pulls in weak signals easily and as a result, your speed will increase 3 x on the download(mine did, used two online speed tests to check the performance when I recd the alfa unit)
There is a post on here from me about this unit and the gentleman who took my advice and bought the device on ebay; if you go through my posts, you can read about it.
Quality drivers come with quality wifi adapters; Netgear, Linksys, Dlink are all second rate companies with overpriced inferior products.
For your purpose, for wifi hopping or "war driving" I recommend this product.
When I download files in the evening, the transfer rate is over 525Kbps!