I recently bought an
Alfa 2000mw 2W Waterproof Marine high power Long Range Outdoor 802.11 B, G, N, USB wireless network Wifi Adaptor with Integrated 12dBi Antenna. Even though I haven't mounted it outside yet, using it inside the RV has greatly improved use of the park's wi-fi. It was very easy to set up and comes with a CD with needed drivers and a configuration utility. I can highly recommend this item.
At the same time, in order to set up an access point within the RV so both DW and I could be online at the same time, i got the
Alfa R36 802.11 b, g N, Repeater and Range Extender. It works great once you figure out how to connect the adapter and communicate with it. As delivered, the R36 does not support that adapter - you have to download a firmware update and install it in the R36.
Instructions for accomplishing all this are terrible, but at least the ALFA support team is quick to respond to email queries. It took me 24 hours to finally get the set-up working, and it does work very well. You might want to read ALL the Amazon reviews on the R36 before deciding whether you want to tackle this thing.
Ted H.