I have a MBP from mid 2007 (UK). The battery life has suddenly dramatically decreased. I used to get 2 hours and now less than 1. A 15 minute video clip ran it empty the other day, from a full charge when disconnecting. I am thinking of replacing the battery but am not sure which battery to get. This battery was a warranty replacement from Apple but the mac is now out of warranty. It was charging when the info below was copied (45% charge). I have always done what Applecare told me to, which is to regularly discharge it completely by running it on wifi, then recharge fully. The cycle count looks quite low to me for it to need replacing.
How long should you get on web use for eg (including a few youtube clips but mostly web pages) on a MBP 07 battery?
Current battery details are as follows and any help much appreciated. thank you

Battery Information:

Model Information:
Manufacturer: Sony
Device name: ASMB012
Pack Lot Code: 0001
PCB Lot Code: 0000
Firmware Version: 0110
Hardware Revision: 0500
Cell Revision: 0303
Charge Information:
Charge remaining (mAh): 1418
Fully charged: No
Charging: Yes
Full charge capacity (mAh): 3123
Health Information:
Cycle count: 229
Condition: Check Battery
Battery Installed: Yes
Amperage (mA): 1553
Voltage (mV): 12255