Parks at a local town provides free WiFi. It requires no password to use. But at some area the signal is very weak. Can I use the extender to make the free WiFi stronger?
Not unless you have access to the router that is providing the wifi. You would need to access the router every time you wanted to use the extender. If you're an owner/employee trying to extend the range, you probably could, but as a citizen, probably not.
I think you would need more then one depending on your source. However, by doing that your speed may decrease. It should help but of course walls decrease the signal which decreases the speed.
Possibly. It depends on variable factors since the garage is unattached. Only way to find out is to try it. Just buy it from a source that allows returns if not satisfactory.
I might suggest buying a travel plug to plug into the 220 and then you plug it into that. went to France/Ireland used my travel plug and then plugged my Mac into that, worked fine. I don't know why the wifi booster would not work fine.
The Ethernet is both input and output (as are all Ethernet ports). It is 100Mbps full duplex (can tx and rx at the same time). It is intended to be client facing (e.g., connect your laptop, your desktop, etc. to it so that you can have a wired connection).