Reanult megane 1.6 16v no power what so ever!!??

What happened was, the battery wen flat and wouldn't start. so i got jump leads and use my van as power source, connected the leads an sparks flew everywhere. turned out that vauxhall(the van) decided to put the red wire onto the negative connection and black to positive????grrr. now there is no power what so ever until i connect them correctly, it start but shows service and stop lights and tells me there's an electronic problem. could this have done massive damage or a simple fuse be blown??? cant find user manual so unable to find out what fuse does what? please help, thanks.