My car's timing is pretty much in that same spot, maybe a LITTLE farther up. I haven't checked my timing, but I'm assuming that it is the stock 8 +/- 2 degrees that the car is set with. Yours isn't extremely high, though. It's pretty hard to tell what timing you have from pictures, but I would guess that you are pretty safe (compared to my GA16DE's distributor position).
Actually turning the dist. towards the firewall advances the timing. Who's to say your timing has been retarded out of the factory spec. You need to check it with a timing light to see where it is set at! Otherwise how are we supposed to comment as to why your car runs the way it does if we don't know what the exact timing number is?