Help!!

I've spent the last couple of days trying to organise all of the internal flights, trains and car rentals for our trip.  It's an absolute nightmare.

I finally found an almost affordable way to travel from Paris to Lisbon and then back to Eindhoven (Holland) and am unable to book it.  Seriously.  I can't get the site to accept my credit cards (which seem to work perfectly well everywhere else on the internet).
So, I have to book it through an Australian site, which wacks on a whopping great mark-up (I know - they have to make money too but it does seem extreme) that makes it even LESS affordable.
I still haven't organised all of our visits to friends.  Especially the ones in the UK.  And we're leaving in 8 days.  Ooops.

I still haven't booked the Eurostar from London to Paris, because until I've established what nights we can see our London friends, I don't know when we'll be leaving the UK.  It would be just my luck to book everything and then find out that my friends are only available the night after we've left.  
And the nightmare and expense of trying to organise car rentals that start in one country and end in another country.  I mean..... what's the point of the European Union if everybody still behaves as though they've got their own currency?!  (I am kidding - all my European readers)
Sheesh.  The extra expense of an "international one-way" rental means that 8 days of car rental from Paris TO Paris (via Eindhoven) is cheaper than 24 hours of car rental from Paris TO Eindhoven plus a train back to Paris.  Crazy.
It's a steep learning curve.  And it seems such a waste to be learning so much stuff about a subject that I may never need again.   Please feel free to pick my brain before your next European jaunt
Ah well..... it'll be an adventure.  That's for sure.