Is it possible to get into a good masters program in computer science with a 3-3.5 GPA?
It's up to you to decide whether to pursue a master degree or going for the industry. However, in case you selected to pursue your master degree I would see no reason to be so pessimistic about your chances. You're currently studying at a prestigious university and that's an important point to consider.

The grades of the last 2 years of bachelor program is so important as you would take most of your specialized courses during the last 2 years of the bachelor program.

Be optimistic and keep up working towards achieving your dreams!