Macbook Pro takes 20 hours to charge

I have a 15in mid 2010 Macbook Pro and recently is taking forever to charge. It was fine 2 weeks ago, then I went on vacation and left the laptop at home for a week. When I tried to recharge it after I came back with (battery being 7%), the time of recharge shows up as 20:00. and It actually takes aroung 18 to 20 hours for the battery to fully charge. I have reset SMC, and PRAM multiple times with no effect, I even upgrade from snow leopard to Lion, still no effect. As of now, there's nothing wrong with the laptop other than it takes so long to charge. What might be the problem? Here is my battery stats

Model Information:

Serial Number: < Edited by Host >

Manufacturer: SMP

Device Name: bq20z451

Pack Lot Code: 0

PCB Lot Code: 0

Firmware Version: 201

Hardware Revision: 000a

Cell Revision: 158

Charge Information:

Charge Remaining (mAh): 4865

Fully Charged: No

Charging: Yes

Full Charge Capacity (mAh): 6542

Health Information:

Cycle Count: 309

Condition: Normal

Battery Installed: Yes

Amperage (mA): 270

Voltage (mV): 12044