Cheap DIY FM Antenna

I bought a used Sansui TU-217 some months ago just to have some background music in my living room, I have two questions:

1-There are 2 300 ohm and 1 75 ohm taps in the back of the unit, which one should I use ?

2-My current antenna is a piece of wire connected to the 300 ohm tap. I don't receive some station correctly so I would like to build a small antenna. Thing is I don't have space to have a 3 feet piece of wire hanging inside my living room. Also I live in an apartment so putting it in the roof is not an option.

What can I build that's small and serves the purpose ?

Thanks !!!