OK, good news that it's vertical: one of my machines was configured like that and there was *no* damage despite a massive leak. Even the Real Time Clock worked
. The horizontal boards suffered at least a broken RTC and at worst a total loss of FAST ram as well...
I've bought 10 rechargeable coin-style batteries from Farnell - these should never leak. They cost me just over 3 quid each... I can get you one to portugal for £4 if that'd help? PM me if interested.
First things first though, get that battery off the motherboard - cut it off if you can't desolder it. Be aware that the leak will be acidic or alkaline so try not to touch the leak, and wash your hands afterwards! Clean the board with something like isopropyl alcohol and an old toothbrush (or your wife's)