Can you clarify the following information:
a) Is this a Live Auction in our NP Chat Room you are talking about, or;
b) An Auction in the Domain Auction Forum
If A, Private Message the buyer asking if they would like to pay in $NP or Paypal, and give them your paypal address.
If B, Private Message them with your paypal address, and wait until payment has been received.
After all steps are complete above, ask them for their Dotster information, then push your domain to them. Dotster should have an FAQ on their website about pushing a name to another person.
Thanks,
Josh.