See if someone has an A520 laying around. You can get RF and color composite that way.
Otherwise, you need to find a DB23-SVGA adapter and a monitor which will scan to 15kHz, or a real Commodore/Amiga monitor with cable.
There's also a project here somewhere of an RGB to component converter.
But the short of it is you cannot use a stock A500 with a standard VGA monitor without an un-Godly expensive scan-doubler.
