My battery is dying

My cell phone battery can't even last for a day (after charging) and of course, I do know what causes it. Me as a heavy user of sms-ing, downloading polyphonic ringtones and surfing mobile web. I've been trying to reduce my usage but in vain :p Maybe I should consider putting the blame on my friend too because he kept sending me 2-3 pages of sms-es ( my replies were 2-3 pages too) and that's pretty fantastic Lolz... Wait a minute, my batt is really dying *sob* I guess I need to get a new one.