I was very frustrated with disposable cameras and changed to a digital camera. However, with either camera, I would do the following.
Try wiping the camera over the lense. The more I wipe that area, less bubbles I get in the pictures. Search the SB photo sites for other tips.
Your pictures should not have been blurry unless you were too close to the subject. They may have been poor quality, bad light, not blurry. I suspect the camera was at fault or maybe the case fogged.
When you decide to get a underwater digital camera, I would search SB for suggestions.
Hope this helps - Tom