The "new" model 172 SP has much better seats and adjustable in height also:
These are the rudder pedal extensions from
www.aircraftspruce.com
It might just also be that particular aircraft you are flying, over the years there have been many differences between the models of 172 and even 152.
Or you could try these:
http://www.pilotmart.net/amelia/sear...&subcat_22=163
They have;
