ma_very_newbie

hello : I am very very new to this software and has no background in graphics. But I am extremely well versed in Keynote etc. I bought a vector diagram from online shop. I am able to cut the parts I want to remove but I am left with white seams. 1) how do I get rid of it ? 2) How do i get rid of the words and not leave a white vacant alphabet (the white background exposed) 3) How do I save it to a very high resolution (it picture will be on a big poster) Please help.