As a Graphics Card is installed, so you are most probably running ur system on nVIDIA's graphics. So, there is no point in switching. IMO switching of Graphics is not possible probably.
Intel's HD Graphics will only work if the GPU is taken out of the lappy, and one will never do that unless the GPU goes bad.
How much did the lappy cost you BTW..??
From which shop did you buy..?? One of my friends is also looking for new i5 lappy. So, your info would probably help.