There are still a lot of tickets available for the away leg in Madrid. Go to Tickets for REAL MADRID C.F. in Estadio Santiago Bernabeu Madrid - ServiCaixa I have 4 tickets in the North East Lower (below Spurs official fans) and there are still some left but only singles and doubles, but there are plenty right behind the goal in the North stand.
This is the biggest ticketing agency in Spain, you pay online and collect from a ticket machine at the ground or any of their machines around Madrid. You choose your seat online and it confirms the seat numbers. I had a problem with the website accepting my card initially. The problem was that it didn't recognise the card as being registered with Mastercard's Secure Code system (where you have to enter 3 digits of your password). It worked with my Santander card, they obviously like spanish banks!
Get on there and fill the ground with Spurs fans!!!!
We have flights to Valencia and are driving to Madrid (flights were only £60 with Ryanair, car hire £30) as Easy Jet wanted £1150 for four of us.