(250,000 mph)(24 hours per day)=6,000,000 miles per day
(6,000,000 miles per day)(365 days per year)=2.19 billion miles per year
2.19 billion miles per year/6 trillion miles[1 light year]=2739 years [For the black hole to travel one light year]
(2739)(6000 LY)=16,434,000 years
Relativistic offset:
Because the object in question is 6000 light years away, that means it is actually 2.19 years closer than it appears, or 16,433,998 years from closest approach.

This all assumes that the Sun and our Solar System, would some how stop dead in space for sixteen and a half million years, and wait for GRO J1655-40 to catch up.

The Sun moves relative to the center of our Galaxy at about 491,040 miles per hour. Accordingly, it would be in a much different position 16,433,998 years later.