As it stands right now, you will not be able to watch La Liga on Dish Network or DirecTV. Last year there was one game each week on PPV on In Demand (cable only). It was $14.95 per game. It does not appear that anyone has purchased the rights for La Liga this year. TVE International is available on both Dish Network and DirecTV. They had a La Liga highlight show every Sunday night. I assume they will still have it this year, but we will need to wait another week to be sure. TVE will have the second leg of the Spanish Super Cup tomorrow afternoon. TVE will also have the Copa Del Rey Final.
On DISH you have to purchase TVE as a separate international channel. It's not cheap -- seems like it's around $25/mo.
TVE International is part of the Dish Latino package for $20.99/month. It's also part of the larger Dish Latino Dos and Dish Latino Max packages. I don't think they offer it A-la-carte. On DirecTV, it's part of the DirecTV Para Todos packages ($31.99 or $35.99). It's also part of a package on the Hispasat satellite at 30 degrees west. This is a package of about 10 channels from Spain. A special receiver is required (for about $300), and then it's $100 a year.
Unless I'm mistaken, DishNetwork is required to give you that extra dish for free. They're not allowed to charge you anything more than your original setup so you can get any station. That's why you can upgrade to the Dish500 for free. At least that's how my Telecommunications Law professor explained it.