As some of you noticed, I got my blogger beta template problems resolved this weekend. Thanks to helpful comments from Propter Doc and Skookumchick. I used skookumchick's code to put the picture in as the background, e.g.,
margin:0 auto 10px;
border: 1px solid $bordercolor;
border:1px solid $bordercolor;
But the picture still didn't show up. Turns out that blogger wouldn't show pictures posted in blogger beta (for some idiotic reason). So I had to open a flickr account to post the picture elsewhere on the web and then link to that. This was really the only part that I figured out on my own.
Then, since I had text on my banner image, I wanted to get rid of the text generated by the widget in page elements. But I couldn't completely delete it or my title wouldn't show up in bloglines. So I made it as small as possible (using the edit colors and fonts page) and an innoccuous color (thanks to the tip provided by propter doc). I left the description blank and figured out how to remove the border under #header using the edit html.
Finally, I widened the columns to fit the prenatal ticker and the width of my banner. I couldn't figure out how to the get the ticker where it used to be, so I just pre-dated a post and stuck it there.
These obviously aren't the most elegant solutions, but I hope they help anyone who wants to do something similar.
Oh, and please tell me if you find something hard to read, not showing up properly, or too wide for your screen. I'll do my best to resolve those issues.