Hi MB!
I know absolutely nothing about websites and this bandwidth that you've been talking about. However, from the measures you've taken so far, it would seem that every little "extra" item affects it.
There are a couple of things, that while they may enhance the site, really seem unnecessary. I'm referring to those icons next to each post. The one group, where there's occasionally a little blue question mark - for an instant that makes me think it's a "new" mark. Other than noticing those, I never pay any attention to them. I don't know if anyone else cares about them. Perhaps you could ask.
The other group, where there are indications of how many posts are there, sure - they look nice - but since the number of responses is listed, it really isn't necessary.
Again, perhaps ask to see how others feel about it, but I can't see any real need for either one, and I would guess that eliminating them would help your bandwidth problems.