Welcome to the world of Amigas! If your 512k expansion is cleaned up and has the battery removed, there's a chance it will go on working (although the clock won't keep the time anymore, no big problem). If you don't want to use the bad quality Composite or RF-out from the A520, you can buy brand new S-Video/Composite adapters relatively cheap. These plug into the RGB port where the A520 is plugged in, but give you a much clearer, sharper image, and all you need is a TV with an S-Video input. You can get them here -
http://www.amigamaniac.com and they really help! Using one of these with any CRT TV makes it instantly feel like a big 1084 monitor because of how crisp the display is, and with LCD TVs it's even clearer. It should work with Plasmas as well, provided there's S-Video inputs.
