Changing laptop covers

I own a Dell Inspiron 6000 and the cover has started to seperate from the screen in the bottom right hand corner. I have been told that the plastic is wearing away where the hinge is.

After putting it in to get fixed and paying far to much money, it has broken again. I've been told that if I get new aluminium rails and hinges the problem can be fixed however the aluminum rails only seem to come with the lid when I look on sites for spare parts etc.

My questions is, if I buy a new lid, is it easy to replace? Should I attempt to do it or give it to someone who definately knows what they're doing?

Thanks