What do you need more video RAM for?  At any rate, if you just got it, your best bet would be sending it back and getting it with the Quadro 140 instead of the 135.  Otherwise you can PROBABLY order a 140 from spare parts and install it yourself, but that would be fairly involved, and not recommended unless you're extremly comfortable working inside systems.

You'd have to call them and see if they'd be willing to let you return and reorder without a restocking fee. 

That's the only way to do it - the entire mainboard needs to be changed to upgrade the video.

 

I am using a SW running on GPU and amount of memory needed is 256MB or larger. Thanks for the advise and if I send D830 to Dell, which was purchased about 3 weeks ago, how much cost should I expect?