This was the wifi app that I downloaded Friday night. I downloaded the other recommended on this thread on Saturday. Both are good. The amped app - the first one recommended is a little clearer in seeing which channel is best to switch too. Both are good and I may keep the both on my SGP 5 for a while (though the first one cannot be moved to the SD card and the one that is recommended in this response can.
Thanks to all for your replies. I think that I will skip the repeater and be happy with the single bar when I am not in the same room as the router. It works fine - and I have been able to stream video without a problem. It is very interesting to see the actual signal strength when you use one of these apps.