The starter is a little cylinder that usually sticks out the bottom of the light fixture. Generally they remove with a quarter turn. You can pick them up for a buck or two at the hardware store. They're a little more expensive at the LFS
You'd probably be ok with one angel in that tank. Angels are pretty, but, unfortunately, they get big. Maybe you'd consider rams. You could put a pair in your tank with no problem. Rams are cichlids like angels, but they stay small. They have a lot of personality.
If you keep the light fixture you have, you could probably grow anacharis, java moss, and java ferns. They'd grow slow, but I think they'd survive.