RE: Best mexican food in Austin
Guero's on Congress south of the river make their own flour, corn, and whole wheat tortillas (I always get the whole wheat). They are great for lunch or dinner, and on weekends, they're open for breakfast. I always get the Huevos Montelenos or the Huevos Rancheros for breakfast, and they also serve fresh-squeezed orange and grapefruit juice. Marinated chicken is one of their specialties, shredded in a number of dishes. They also make a true margarita.
Joe's Bakery east of I-35 on 7th is my favorite place in the world for breakfast. I totate between Huevos Rancheros, Migas, or Chorizo y Huevos. They make the best hot sauce on the planet, and they make their own flour tortillas.
El Sol y La Luna on south Congress a few blocks north of Guero's is also very good, but I don't know if they make their own tortillas.
For authentic interior Mexican, go to Fonda San Miguel. You will love that place.
Curra's Grill on Oltorf also serves outstanding food. Try one of their Avocado Margaritas. Trust me.
As for tamales, your best bet is to find a roadside stand. Especially on weekends, if you see a person of Mexican descent selling tamales out of a pickup, you'll be happy with them.