Yes outside is better and higher is almost always better.
Follow electrons advice , you'll not be sorry you got a higher gain/bigger antenna.
The amp may or may not help much depending on frequency in question, local conditions and actual signal level of channel 24.
Channel 6 is questionable none of us can say positively you can or can't get it or how dependable it may be.
Personally I'd test with and without the amp then you'll know for sure.
If the amp doesn't help post again here for a possible tweak.
(wouldn't want to confuse the issue with coax traps)