Well, other than PayPal and wire transfer, they don't do any others. Wire transfer would be pain in the ass as it charges more than 20% of the total wired amount. I'm not in the US, so I hope there is some place where you can send money order using credit card.
You can use bidpay for non-auction payment, at least I have in the past. I remember there beeing a comment box and I just put in there that it was for a non-auction related payment and it went through, no problem.
There was also another service like bidpay, but I just can't think of the name. It was totally non-auction oriented, more for general use. There fees were also less than bidpay's. I'll have to google, see if I can find it.
Like I say, you could go to your local post office or bank, they usually do have Money Order or Postal Order which you can use and they do have US$ denominated ones. The Local Post Office would usually just charge a few dollars for processing and they are as good as gold. They can then be mailed so should not be an issue there.
I understand that you are from Malaysia. Well, check with POS, the last time I checked, they do have US denominated Postal or Money Order.