Can API help me with my text box problem???

Hey everyone,
I have a fairly complicated question.
I need help with textboxes. I use the code, GetLineCount. But i really need to know, can i get the text thats on a certain line, going by a line number? I need all the text on line one "Go to" for example then line two returns "A site". Can it be done? Oh yes and one more aspect to the problem, i don't know the length of each line, the length can change when the user enters something different.
If you could help me that would be great!