Well, in both sentences are minor errors:
“Hola, como te llama usted?” should be “Hola, como se llama usted?”
“Hola, cual es to nombre?” should be “Hola, cual es tu nombre?”
(I guest that the second one was a typo)
In the first sentence you are mixing the formal and informal way. If you want to maintain it formal, use the correction that I gave you....