Welcome back!!!
First get yourself a nice 1200 desktop and fit it with Kickstart 3.1 (if it doesn't already have it). Big plus is some kind of accelerator, a 030 50Mhz is nice with some fastram (16MB or so).
Then get yourself a PCMCIA networkcard which is compatible with the Amiga, install OS3.9 and you're there.
Don't expect to much from Internet on the Miggy though, you can't quite compare it to IE.
Catweasel? go have a look at
www.amigakit.com, UK based and they sell them (and much more nice miggy stuff!)