I have just been admitted to the most prestigious and highly ranked university of my country.
You've confused me as well. Why wouldn't you go?
he is going already:
I am thinking of planning to do my PhD in US after completing my Masters here, so my question is Which level's marks do they give more importance to i.e. of Bachelors or Masters
Oh, that makes sense. To be honest, I don't think most people on this thread will know the answer to that. None of us are on these committees. However, in general I'd say they are looking for the most well-rounded application. My guess is they weigh them fairly equally, but I also know that some schools here like their students for the whole duration of the professional degree, so they can get more out of them.