As indicated by the fact that you had to ask if you could pull a 3.5. If you get a 4.0 for the next 7 semesters taking 17 credit hours, you can get a 3.83. To place your GPA halfway between your current GPA and 4.0, you need as many credits of A as you currently have. To place your GPA 3/4 the way between current and 4.0, you need twice as many As as your current credit hours.
Notice also that 12 credits of A next semester will yield you approximately the same GPA as 18 credits of B+. This may seem like a tantalizing option to avoid having to get As, but it will make it much more difficult to raise it from 3.6 to 3.7 down the road. At the very least try to maintain a GPA halfway between your target GPA and 4.0 for the rest of your ugrad career.
And take some time to understand GPA well so you can make decisions about classes in your best interest.