For me, this sounds, like the starter motor engages, but won't crank the engine. Have you checked your battery charge?
If the charge is OK, it might be the "brushes" (I hope, this is the correct expression. It's the sliding contacts on the starter motor rotor) Nothing really expensive.
It doesn't look very classy... but if you come along this problem, and you give the starter some "technical tapping" it might work, and start. Not a permanent solution, though..
I had the same symptom on one of my former cars. A 100gr hammer was my permanent companion, that time.
Good luck,
Ivo
)
