wired/wireless questions

Hi all,
I have a few question about the issues i'm trying to resolve.

I recently moved into my own house from a much smaller apartment

in my old apartment Approximately 100QM (1,076 SQ Ft) I ran a simple linksys wireless G router and it easily covered the entire single floor.

In the new house Appromimately 250QM (2,691 SG Ft) over 3 floors the Linksys covers the 1st floor and small parts of the 2nd. In germany the buildings are pretty much made of steel reinforced concrete so WIFI doesn't stand much chance.

I would like to set up my home office on my 3rd floor obviously i can't use WIFI with my current situation.

The phone/DSL connections are only on the 1st floor near the kitchen so there is really no way to move the router easily to the 2nd floor where entire house coverage might work.

So, there is a cable tube from the 3rd floor to the basement, yesterday I bought a 25M cat 6 cable and 2 plug boxes. I have terminated one end on the 3rd floor with one box and ran the cable to the basement I followed the color code listed in the plug box as best I could since there weren't any striped cables only a solid color twisted with a solid white cable so i took each solid white as the striped (man, I hope that makes sense).

the second plug box I will mount as closely to the the router as I can, at this point i think it will end up at the top of the basement stairs, this brings me to my 1st question, having already wired the one box following the color sequence, do I need to match the sequence on the second box or reverse it somehow? I have yet to find a diagram on Google or anything else yet.

once the cable is completed with the boxes i'll run a short patch cable to the rear of the router, (does this cable need to be crossover?) thus hopefully making the plug in the 3rd floor live.

I would like to upgrade my linksys to perhaps an airport extreme and maybe an airport express on the 3rd floor, any idea if this will offer the most coverage of my house?

I hope that i have not confused anyone on this with my long drawn out explaination.

Thanks,
Shawn

first off, in a wired network, (like your's now) make sure all the cables are in the same order.
however, my advise would be, (considering your router also has output connections) place your router downstairs, run the cable from the router to upstairs.
and perhaps buy a little airport express.. should work fine with good speed as well.