I assume by "Bridge Camera" you mean a Super-Zoom? If so that's what the SX100 IS is...
http://www.dpreview.com/news/0708/07082004canonsx100is.asp
Now in your deciding whether or not to get a new camera or not consider this: say a professional photographer wants to photograph using a top of the line Canon 1Ds Mark III along with a top of the line wide lens... this professional photographer (we'll call him Bob) sets all his settings manually so that he can get the photo looking just how he likes it. Now you come along with your Canon SX100 IS and try and take a picture of the SAME landscape. When you've both taken a hundred or so photos (or at least he will have... I have no idea how many photos you shoot at a time) you compare photos. Who's photos look better? Well, obviously, Bob's do... he's a pro with a camera that an average person can only dream of having. But what if you switch cameras... give Bob you SX100 IS and yes... that means you get to actually use that beast of a Mark III. Bob quickly switches to manual mode as that's where he's most comfortable and you either switch to auto mode or try to impress Bob by fumbling around in manual mode, either way your pictures, even though they were taken with that glorious Mark III, probably won't be as good as Bob's taken on your SX100 IS. That's right a $200 camera taking better pictures than a $7000 camera.
These are probably the kind of images you're hoping to achieve with a Canon Rebel:
It might surprise you to know that both of those photos are taken with a normal Canon SX100 IS... just like you have.
As I think this photo proves even an SLR can (and definitely will) produce bad photos:
I just found this photo on the internet... it's taken with a Canon Rebel XTi. I don't know about you, but it reminds me of the first time I went out and tried to shoot a sunset with my camera (a Fuji Finepix S700) which is fairly similar to yours...
Then I went back another day and got this:
Same camera, I just had a little more knowledge and experience.
So here's what I would recommend... master your camera's manual mode (get a book like
Understanding Exposure) and then once you have the manual mode mastered and have given it some time see if you still think you need a new camera... if you still are interested a DSLR just may be for you.