windows server 2003 enterprise

I am trying to do the following i have a windows 2003 server that runs off a business class dsl line thats connected to a linksys wireless router i want to implement a vpn but also be able to access the internet and have the other wireless computers access the server.. I am having so many problems i create the user installed the vpn its up and running and a file server to test it out i go online via dialup and try the vpn into the server it connects and it says veryfying the user name and password and then it says cannot access the server.. can someone please explain to me how to get this work or if i need to purchase an additional card one directly to the dsl and one sharing the dsl line to the router either way i need to get the vpn working makes no sense to me why it doesnt work please help