1) Not many schools offer the spring intake... I personally do not think the spring intake would be a great idea because a summer internship is a very important part of the US MBA (especially for people looking to change careers).. You might want to reconsider your plan taking this into account...
2) Anyone looking to evaluate your profile will need a few more details :
What you plan to do after MBA
Your achievements, promotions, responsibilities at your current firm and the reputation of the firm
Extra curriculars if any
That being said, a 610 is a little below the average (especially for an Indian applicant) for maybe the top 50. You mght want to consider retaking the GMAT if that is what you are aiming for..