When you arrive, thank the Buddha for realizing your mother's wish in front of your mother's wishing icon, and explain that your mother really can't make a wish in person because of work and family reasons, so she chose you (son/daughter) instead of her mother.
In fact, as long as your mother is sincere, it is the same everywhere. No matter where you are, all buddhas and bodhisattvas can see what you are doing.
The specific support is not clear. Since your mother promised, when you get to the temple, take the money to find the monks in the temple and explain the situation. They will tell you what to do.