A couple of comments -
What material is the condo made of? Brick? Stucco? Wood with siding? This makes a big difference in the amount of signal indoors. Regardless, your TVFool report does not account for these conditions at all - it assumes unobstructed mounting in clear air. Any trees or buildings between you and the transmitter will greatly reduce the amount of signal in the air.
Next, if you own your condo, by law the HOA does not have any say in whether you put up an antenna or not.
http://www.fcc.gov/guides/over-air-r...n-devices-rule
A small antenna like the Leaf will not be very sensitive to VHF stations like WRCW 5, KGW 8, KOPB 10, and KPBV 12. You can ignore the station numbers that the TV displays (20.1, 38.1, etc) and look at the real channel. This is the channel that the station actually broadcasts on. Chs 2-6 are VHF-low, 7-13 VHF-high and 14-51 UHF. Unless there is just a huge amount of signal at your location chances are very slim that you will see the VHF channels from a small flat antenna indoors.
If you want to try a more VHF-friendly antenna, a pair of long rabbit ears will be better than the flat antenna (which is more suitable for UHF).
An amplifier is not a panacea. All it can do is amplify whatever TV signal comes from the antenna, at the cost of some added noise. This won't necessarily help you.