I have the exact same camera, and had the same problem. Not sure if i am recommending the same battery as already mentioned, but i now use a lithium battery. My fab boyfriend bought me some which look like two A4 batteries joined together. They are:
Panasonic
CR-V3
3V Lithium
I have only used one so far for many many photos. I know these are more expensive, but more than make up for it, and i know he bought them very cheaply from an internet site. Would highly recommend!