Is ther is external graphics card for laptop

The only commercial product is the vidock but expresscard creates a big bottleneck. You'll have to wait for usb3 or thunderbolt to become more popular for other solutions (although these connections still bottleneck). Or you could look up current diy solutions.
 
Actually Vidock is a viable solution as stated above. There are three versions; ViDock 3, ViDock 4, and ViDock 4 Plus which ranges in price from $200 - $280 + shipping charges.

http://www.villageinstruments.com/tiki-index.php?page=ViDock

These are only external graphic card cases. You still need to add the cost of the video card. It doesn't specify which USB version is supported, so the natural assumption is USB v2.0. It's not as fast as an actual PCI-e interface, but if you want an external video card, then this is your only solution.

Have fun....