Yes Blau and Simyo along with a few more are part of e-plus Moviles S.A. which again is a part of KPN. All their networks are MVNO's and piggyback on Orange. It appears you only have 2G (GPRS) coverage of Orange, so Simyo will also not help you.
Have you looked up coverage maps of all the networks by any chance? You can find these on the company websites and even on sites like GSMWorld etc.
The Yoigo test suggests you also only have 2G coverage for Movistar, and as expected none on their own Yoigo network.
So unfortunately it looks like you are stuck on Vodafone, who are the only ones who appear to have 3G coverage where you are. I am not that familiar with other MVNO's that use the Vodafone network in Spain. (i.e. Piggy back networks). I know Yoigo have a deal with them, but unfortunately only for 2G data. Their 3G roaming partner is Movistar. There are probably about a dozen MVNO's on Vodafone. I think BT are also with them, but I am not sure of their data rates (or if they have).
For a list of some of the MVNO's in Spain see:
Comparativa tarifas móvil low cost: Movistar, Vodafone, Orange, Yoigo y OMVs
Unfortunately, no data rates there.
Also, have you considered traditional wired broadband? It may be a much cheaper option for you!