Hi Gary; you may want to check out the Fanfare dipole ($85). If you have your own home, and don't mind mounting a 200" boom, go with the APS-13 from antenna specialists (see my review on AudioReview).
NO MATTER WHAT: You will need an antenna that it outside, mounted high, away from power cords and tall buildings/trees. FM travels accross the ground, and is "line of sight." If you are near (within 1 mile) of really tall buildings, you will really need the gain of an outdoor antenna mounted about 6 feet above the roof line.
FM is located just above ch 6 (TV) and wll below CH 7, so the radio shack antenna is about as good as you'll get indoors. There are some that offer "amplification," but that usually means amplification of EVERYTHING, noise included. There are exceptions to this; let's see if others chime in who are in a similar environment to you...
You have a very nice tuner; but it will require a proper antenna, no way out of it! I have been researching this for over a year; it is very complex once you get into the nitty gritty of it.
I would try the $85 Fanfare (Don't get the "other" one, which is a knock-off of the Fanfare), follow the instruction carefully - very carefully - and see how that works. IF it does not satisfy your needs, you'll need a directional antenna like the APS-13, which I love (It requires a rotor and a rotor box w/remote).
Good luck and let me know how it goes,
-Kurt