Need help with blog design...

I think I am still using the old Blogger "stuff". I tried to change my template and my colors and can't seem to get to anything that will let me do that. (I'm thinking it's because I didn't change to the new blogger when some of you did...and now I am stuck in "Nowhere Land"...unable to change background or font colors or template....and can't make the photo at the top of my blog appear larger like I used to be able to do.) Can anyone offer any suggestions?

As it turns out, I don't have a lot of time to fool with it this week, either, as I'm getting the house ready for our house-sitter to arrive. Hubby and I are going on a roadtrip and there is lots to get ready in addition to making the house comfy for the sitter. BUT...I really hate to go off with my blog looking so dull and lifeless.

So...if any of you have any ideas of what I might be able to do quickly and easily over the next couple of days, I'd be interested to hear about it. Thanks (in advance).

NOTE: Edited to add: I did click on Design and then Designer Templates. That is how I've changed things in the past, but....now I get a gray screen and there is an empty box that says "Live Blog". There are NO template options presented to me. There are words on the left side such as Background, Layout, and Advanced. I can click on each of them but get no options with any of them, either. It seems as if my blog is permanently stuck and no changes are able to be made now. It is so discouraging that I am half tempted to close my blog down...which I really don't want to do, but I can't just leave it unchanged...especially since I don't like the way it looks now. I did have the new version of Blogger for about two days several months ago, but then I changed back to the old version. I am wondering if Blogger has, somehow, put a "lock" on those of us who never went to the new version?