If it were mine, I'd be tempted to use 6 x 6 treated (incised) posts, set in concrete, below the frost line--both for their additional stability, and their ability to be notched and through-bolted at the header connections (as joecaption suggested), making a far more rigid and stable structure. And I don't think I would ever rely on concrete block, or especially the lighter cinder block, to attach a ledger to. One heavy snow event, and it's all over, with the entire wall pulling out and collapsing. Much better to make the carport free-standing, with 6 x 6s adjacent to the block wall to support a "high-side" header at any elevation you want. Could even cantilever the joists/rafters over it, taper-cutting the ends to enable the roof sheathing to butt up to the garage roof, with flashing tucked under the garage shingle-line you intersect.
Something else to think about--if you're using 2 x 6s for joists/rafters, put them in at 12" centers. Much less deflection under any load than 24", with better performance. I don't think you mentioned a span length, but 2 x 6s at 24" centers are pretty much maxed out at a span of just over 7', using an allowable bending stress of 1500 psi, allowable deflection of L/240, and a 50 psf live (snow) load.
Thinking outside of the box, why not consider building a complete roof now, tied into the existing garage full-height, coming off as a "T"-eed gable? That way, you wouldn't be tearing things out and re-doing them in a year or two, but simply infilling the walls and floor to make a "real" garage addition when you can afford it.