The best antenna location would be one with an unobstructed view to the north. From your description, I gather you have a north facing window but it's not as convenient to use as an antenna mounting location...?
For those limited to indoor antennas, I often suggest the Terk HDTVi (not HDTVa) which supports both UHF and VHF reception. The UHF section of the antenna has a bit more directivity than most other indoor antennas, making it capable of reducing the effects of signal reflections (multipath interference) to a limited degree. Reliable reception of DTV signals is more an issue of signal quality than strength. Amplifiers will not fix a signal that has been distorted by reflections off of buildings or passing through vegetation.
(Amplifiers and well pumps are analogous in a way; If you were seeking clean drinking water, you would not expect a high pressure pump to make dirty water from a ditch drinkable... just high pressure dirty water... you would dig a well deep enough to get clean, clear water... the pump's job is to push the water through the pipe to the faucet. So likewise, an amplifiers job is to push signal through coax and splitters... but you have to give the amplifier a signal worth 'pushing' to begin with.)
http://www.amazon.com/Terk-Technolog.../dp/B0001FV36E
Is it possible to place the antenna at the north window and extend the cable to the desired location for the TV? Local big box home centers and electronics stores have the parts in stock.
http://www.homedepot.com/Electrical-...1#.UNA0-qw4R74
http://www.homedepot.com/webapp/cata...ll#/?c=1&lo=lo
http://www.radioshack.com/product/in...ductId=2103648
http://www.radioshack.com/family/ind...w=Coax%20cable