You should easily be able to find an appropriate power supply on Ebay. Some come with multi plugs, one of which will probably fit the Asus. Otherwise just cut and solder your old plug
I also use an old power supply, as the previous poster (good post Raas. I'm still using your Headstart 2. Going great). Found a suitable plug in my bits bin. The Asus plugs are nothing special.
Some people I know use an 6v or 12v SLA battery on trickle charge. You can use this to step down to 5 or 9 v for all your gear.
http://cgi.ebay.com/AX3022-Based-Swi...06164001r18533
I get some of my odds and ends from http://www.jaycar.com.au/printed.asp as there is a store down the road. They do mail order. Ebay from a Hong Kong supplier is probably cheaper.
You have a lot of options. Forget getting the plugpack from Asus
