If you are lucky, it will be as simple as reconnecting the linkage, as Klaus described.

I was not so lucky. When I replaced mine in March 2005, the r/h door lock (p/n: 8628224) cost $117.97 plus tax at the dealership.

The repair procedure may be found here:

http://volvospeed.com/Repair/v70latch1.php

I doubt that you will wish to try to repair the "Red Evil Plastic Lever", so just follow the instructions for lock removal and replacement.

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Dave in Virginia; 1998 V70 T5(M): IPD MOTRONIC+ ECU Upgrade, Sport Muffler, IPD Strut Tower Brace; VDO Boost Gauge, IPD Anti-Sway Bars, Rocha ABS Control Unit, Koni FDS Struts and Shocks/// 1988 245 DL Wagon// 1967 MGB Roadster

That's not easy and depends what is broken. Usually if the button goes up and down, the lock will work. There is a link between the perpendicular rod and the lock itself which might have come undone. You will have to remove the door panel to inspect it.
If it is the lock, the entire lock will need to be replaced, which is not cheap unless you have access to a pick&pull.

Klaus
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Volvoless. Sold the R. There is now a void...