A single Kickstarter account cannot make more than one pledge. If you are interested in upping an existing pledge, you can do so by simply returning to the project page and clicking
For instance, say you want 2 x $99 backer rewards. Simply increase your pledge to $198 to the Kickstarter and send us a message to let us know.
We will get back to you with a confirmation letter once we have added you to our special request/international back spreadsheet. We are more than happy to work with you to get you the rewards you want.