Im havin problems wit my degree program?

I am a US resident who had my green card recently. Currently i am follwing my computer science degree at my home country Sri lanka. my degree has 2 aspects, a normal degree completes in 3 years and 4 year degree which offers B.Sc.(special). I am now in my 3rd year and i want to know that, if i get the normal degree in 3 years, will i be able to apply for a M.Sc. program in a reputed university at USA. or is it better to get the 4 year degree? plz help me.