Are connected to 3G or Edge connection continuosly? If so then that is probably part of your problem. The 8525 has a history of poor battery life. You can goto the HTC website & download the WM5 ROM for HERMES which is the same as the 8525.
HTC - Touch Phone, PDA Phone, Smartphone, Mobile Computer
HTC/ATT did release WM6 but they only had it posted on the website until Febuary.
XDA Delopers do have the WM6 ROM on their website which is the officail one.
XDADeveloperWiki - Available Original Shipped WM6 ROM Versions
AT&T Cingular WWE update_me 3.62.502.3 update_me 1.54.07.00 32.86u.7020.23H 18128.0.4.4 update_me update_me update_me 1