I have 10 months' experience of 2 companies altogether and my graduation aggregate is 58%. Will it affect my final placement after MBA?

Not many companies look at the graduation scores as a criteria for shortlisting, but there might be a few who would consider the same. Be prepared with an answer for it, also try to score well in post-graduation to cover up a bit. Any B-School which you want to enter will for sure give some weightag