One thing you could try is to add a "shorting stub" tuned to 103.7 MHz to the antenna of your receiver. The point of this shorting stub is to "short out" (attenuate) the 103.7 MHz signal, and leave the rest of the frequencies (somewhat) untouched.
This configuration works best when you use an external antenna with your radio. If your radio only uses an internal antenna (such as a collapsible metal antenna), then this procedure may not work.
For now, I'll assume you can use an external antenna, and that your radio has two screw lugs for attaching one to the radio. We will want to connect this "shorting stub" directly across these two terminals for best results.
A piece of 300 ohm twin-lead, which you can probably still find at your local hardware store, should work best to make the shorting stub.
One end of this twin-lead will need to be attached to the radio (antenna and ground lugs). The other end of the twin-lead will be shorted together.
Start by shorting together the free end of the twin-lead. (Just strip and twist the two sides of the twin-lead together.)
Measure up from this now-shorted end exactly 3 foot 10 and 11/16 inches. Mark this point (don't cut it yet!).
Now figure out how much extra wire you will need to attach this stub to the radio's antenna and ground screw lugs. It is very important that you do your best to minimize the "extra" or "slack" here. Use the least "extra" wire as you can. Add the smallest practical amount of wire you need to connect to these lugs as you can to the stub you have made so far.
If you make a mistake, twin-lead is cheap, so start over.
Once you attach this stub to your radio, move your FM antenna around to see what position works best to null out the 103.7 MHz signal.
There is a strong possibility that your stub will reduce other signals on the FM band, but you might be surprised to find that you have at least some that will still work for you.
[Edited to correct length. I used "low-pass" formula, needed "fundamental" formula: (492 / f(MHz)) * 0.82 - Where 0.82 = Velocity factor of 300 ohm twin-lead]