a converter
 

i need a program to convet avi to mpeg, im sure theres one out there but i can't find it, any idea's
oh and it has to keep the file the same size or a little bigger is ok

Have a look at vcdhelp.

They should have detailed description and the necessary tools!

TMPGenc is a program that can do this, you can download it at :
www.doom9.org or www.divx-digest.com .
On both this sites I think there are manuals also on how to use it.