I agree with everyone who is saying that your current setup looks backwards for that type of bike.

But I also question your original assertion - that you have too much weight on your butt. That is exactly where the weight ought to be - you do not want to support yourself with your arms. If your butt is unfcomfortable, I'd suggest trying a different saddle before you go through the heartache of changing your bars. Also, try wearing bike short, mountain bike shorts, or underwear with padding. With spandex bike shorts you can always wear regular shorts over them so you don't look too roadie-like (I'm a roadie "by night" and I do that all the time when using a bike for errands). You'll be amazed what a difference that makes - I have a saddle on my single speed that hurts after a mile in normal shorts, but that I can ride comfortably for 30 in a good pair of bike shorts.