Bridge DSL from old office to new

We are moving our office up the road, our DSL provider pushed back the date for moving our service beyond the moving date. I have to come up with a way to move our email from the DSL line in the old office to our exchange server at the new location. I set up a computer at the old office to receive the DSL and dial into the servers at the new office, I can route incoming mail to the exchange server, but outgoing mail will not route through the dial up connection to the DSL computer. Does anyone have any suggestions or ways that I could accomplish this??