can you transfer original ipad to iPad retina?

do you mean the data and content?

Backup the ipad 1, then restore the new ipad from that backup.

How to Transfer Everything from an Old iPad to New iPad

http://osxdaily.com/2012/03/16/transfer-old-ipad-to-new-ipad/

If you mean update the display of the actual iPad then no you can't.

And if you mean exchange one for the other, you can't. You can sell one and use the proceeds towards the purchase of the new one.