Can you get larger batteries for sony vaios laptops?

I have a sony vaios laptop and it came with a 6-cell lithium-ion battery, is there anything better than that, because i have a full battery charge, then i spend 2 hours with Visual basic, Notepad++ and maybe adobe photoshop/Illustrator/Dreamweaver on (not all three adobe programs at once) and the battery is already done. Is there anything i could do to improve my battery or laptop, because i just got the laptop not to long ago and batteries cost alot.

Is keeping it plugged in not a option? Cause even with a better battery, you'll get maybe another hour or so depending on the workload.