I had come across a website not so long ago that has been a great help for me and Noy, Just thought I would share with you. Topup DTAC, 12Call and TrueMove worldwide. Here you can purchase credit (mobile money) from your GF, Friend, even yourself in Thailand. The credit is added directly to the phone number that you require. The prices are higher then usual as they have added a fee onto the price. I think 100B credit would cost you $US5-6.

It has been handy for me and some nights Noy will run out of credit and unable to get down to a shop, This is not instant, could take an hour or so but confirms with an SMS.