Possible to get new seat cushion ?

[mfn1194]

With 50K miles on my G35 the drivers seat bottom seams a bit sunken in. Maybe the previous owner was a big guy, I don't know.

Is it possible to have new "stuffing" put in the seat bottom to make it firm ?

I like a firm seat, not sunken in.

Any ideas where I could get that done, and how much it would cost ?

Thanks