With a 2.1 you would need atleast a 170 not to get auto-denied by almost every top 50 school. 175 Would get you into some. You have NO SHOT at Stanford, even with a 180.
Unless maybe if you worked in engineering for 10 years and then went and got a great LSAT(175+) and then applied, but out of undergrad no chance in hell even with a 4.0 in an MBA program. Anyone under a 3.5 really has no shot at Stanford no matter what their LSAT score.
Law School Predictor
Law Score Numbers
As for your original question about masters degrees and law school admissions.
Having a Master's Degree is a soft factor(its way down there though, its rated lower than letters of rec and work history).
The LSAC, computes ONLY undergrate coures taken during your (first) undergraduate degree.
If your school counts withdrawls as punitive, LSAC counts them as F. If your school uses +s and -s, LSAC computes + and -s(A- = 3.66 etc). LSAC counts ALL courses taken and graded. So if your school does grade replacements, those dont matter LSAC will use both the original grade and the replacement grade to compute GPA.
Law school admissions is roughly 60% LSAT 35% GPA and 5% other stuff. Some schools GPA means more than LSAT(Berkley, UT, etc).
Put it this way, I have a 3.13, if I somehow pulled a 180 out of my ass, the University of Texas(15th) still isn't likely to accept me.
There was movement in almost every schools 75th/25th GPA this past year. Some also had sizable movement in their 75th/25th LSAT. Many schools didnt take a single person off their waitlists. Law schools have become harder to get into during this recession. And once numbers go up for top schools, they are unlikely to ever go back down.