Hi Prithviraj. The GA242 uses two belts: one connecting the motor to a brass pulley underneath the body inside a box and the outer large belt connecting pulley to sub platter. Both these belts should be available with dealers of dvd / vcr belts. Original belts may be available in European markets. I recently bought a DVD and VCR belt kit of various sizes at Champion Rubber in Lamington Road Mumbai. Total cost was ₹100 for both kits. The belts last a long time on this reliable TT.
As regards cartridge, an Audio Technica AT3600L is a nice low cost cart. Do not buy newer AT VMN series as they screw down from top and cannot be easily fitted on the GA 242.