First of all be sure your WAP = wireless access point\wireless router is N capable.
You may not even need N for that distance. Having said that, it is the new standard with the best advertised
speed and distance coverage.Explanation of Mbps
You may or may not see an Internet speed difference. But it is not that your Internet speed has really increased. It is the fact that the transfer rate between your PC and WAP have.
I have ordered a few Rosewill products. They get pretty mixed reviews. Seem`s their stuff either works well or not at all.
The other two manufacturers are reputable and seem to make quality networking parts.
IMO, I would not buy them from Amazon.
When I buy parts for a PC I buy from a retailer which is a bit more specialized. Just my .02