Just to add to Steve's reply , outside of san Isidro there is no need to deal with the touts , and they are mostly not very nice people . When they come up to me I put on my broadest Scottish accent, they might speak English but they dont have a hope in hell in understanding me, last time I done this another tout went up to the tout who was speaking to me and said under his breath "es de alemania" which made me smile inside.
You should be able to pick up tickets for all of the ocho naciones series , which includes the 19th , and you dont have to goto the bullring, FNAC is the official seller so you can get your tickets at sol for the same price.
Pity your not going on the 26th , my mates fighting that night.