Goood advice on Uk visa application?

i got an unconditional offer to study in UK,it is a pre-masters course after which i will be guaranteed entry into a masters programme.my question is this:do i have to give evidence that i can fund the maintainance and course fees for the pre-masters as well as the masters programme or will i just have to just give evidence for maintainance and course fees for the pre-masters only .also what duration of visa should i expect ?