The exact same thing happened to me. Because of a low GPA, I was conditionally admitted, and i will have to mantain a 3.0 gpa, just like you, for the first 15 credits. And I am concerned I may have lost the assistantship because of that. The admission criteria for the university, however, was a minimum 3.0 GPA, and mine was above 3.0. I wonder if there could have been a mistake? Even though your post was from 2 years ago, I wonder how it turned out, has anyone here had a similar situation happen?
Would anyone know if, for international students, they take into consideration the GRE score over the foreign undergraduate GPA?