Redesign - Help!

When blogger gave me some new knobs to twiddle I had great fun experimenting with you this blog looks. But I've come to the conclusion that it my attempt to design a blog was ugly (this was helped by everyone I knew telling me it was ugly). I decided I wanted my blog just to be black text on a white background with a really simple banner. I made myself the banner (in paint - that was fun). I've put it up the top, but it just kind of sits there, it won't resize itself, I can't seem to centre it in the page - so it's just kind of funny looking. Help advice, or even just telling me to go back to the Minima template (which has always been my favourite but it misformats in a way that really irritates me), would be welcome.