Thanks. Upon further investigation I don't think replacing the screen will fix my problem.
The crack on the screen isn't really the issue; it's the discolouration of what is displayed. I think this is because the LCD is damaged, which costs a lot more to replace than the glass screen.
The touchscreen ability still works so I just have to guess what is under there (the lower half of the keyboard is unreadable). I will use it like this until I get a new phone.