I don't know how much I can help, I have just started using premiere pro as well. But well, I am just going to tell you what I do.

First most avi files that you dload, will be xvid or dvix and premiere does not like these so I reencode as wmv the episodes I will use before importing them to premiere . For that I use Riverpast video cleaner ( http://www.riverpast.com/en/prod/videocleaner/) I could email it to you if you want . your newly encoded file will only be a little bigger that the avi file, but not much more.

when I export , I choose microsoft avi and no compression, so first I will end up with a very big file ( 2 to 6 gigs) depending on the frame size. Then I reencode that file using either window media encoder, or virtual dub, one way or the other, your file will be pretty small. 10 to 50 MB for around 5 minutes, depending on frame size and quality. If you need the river past encoder, let me know. Hope that helped a little. I have noticed too that there is nothing out there for premiere or very little !
Of course I Am no expert and there could be a much better way to to all this, which I 'd love to know if there is :D