How can I get two routers to work in parallel on one ADSL line?

I have two routers that I need to share my single ADSL enabled (Tiscali) domestic phone line. In order to access the Internet though I can only ever have one of the routers connected to the phone line, i have to physically remove the phone lead from the other router. This is a pain as it means I can;t access the internet when working in my garden office and using Router A whilst my wife uses the PC in the house which is connected to Router B. I've tried using a single router, but the distance between home and garden office is too geat, even trying N series and extenders. If I could just get the two routers to work in parallel with my single ADSL line then that would solve the problem. Is there any specialist piece of kit that would do this for me?

That can be done, but it's a pain....write me if this option isn't better, and I'll explain how to do it:

Best option...almost all brands, especially Linksys, make "range extenders".. You just configure it to hop onto your wireless, set it closer to where you want to surf, and it boosts the signal.
There are also much larger, and even directional, antennas that you can buy to do the same thing. Any of these would be easier then what you are asking.
You can even use your other router as a range extender if you configure it right and put it in AP mode...or router mode if that's not supported. Your "main" is in "gateway" mode right now.

You can use CAT5-e shielded wire to distances up to 253 feet. Try running one DSL to one router. Then use Router B as an "ap" unit "access point". make an eithernet cable and extend the garden office router as close to the main unit as possible. The standard configuration of a router is far less than the "AP" connectivity. try the combination, you'll be glad you did.