Could you please post a link to your TV Fool report (it will look something like http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%xxxxxxxxxxxxxxxx)? The helpful folks here can do a better job of addressing your issues if they can see the technical details of your OTA environment.
Some general comments:
>> Stucco walls have a wire mesh internal to them that blocks signals, so you definitely want your antenna outdoors. You will lose a lot of signal if you try to go through any of the stucco surfaces. Above the garage or on the roof are good locations for an antenna.
>> Choosing an amp will depend on how strong your signals are. If your signals are very strong to begin with, an amp might be a bad idea because they are not good at handing very strong input signals. If you do have very strong signals to start with, you probably don't even need an amp. Conversely, if your signals are not that strong, an amp would be good for distributing the signal to many TVs. It would really help to see your TV Fool signal report to figure this out.
>> If you have multiple branches feeding TVs throughout your house, remember to "cap off" any unused ports with a 75 ohm terminator (like
this). Any open ports on a cable network can potentially reflect signals back into the cable, creating some self-interference that can easily be avoided.