you have two choices here, go with a TV set which has some kind of video input and use a A520 modulator, or get a
.htm]scandoubler and use a PC monitor. Scan doubler will give you better result, but will cost you more.
when going for the modulator, keeping mind that NTSC/PAL units are different, so you'll be wanting a NTSC one.
also this guy
will be producing some s-video/component adapters for NTSC, it seems to be a good compromise of price/quality. (not really sure how much he will ask for them atm, but will probably be less than the scandoubler)
a scandoubler is universal though, so you may go PAL in the future if you want access to more European software.
btw, amiga mice are different to PC serial mice. Never ever connect a PC serial mice to your amiga, spare some bucks and buy a authentic amiga mouse.