Try to get a double channel ( 02 nalli) kabli one (ranges bw 6500-8000) single nali wala would be a bit cheaper than this.
U can also get qoutes / advices from Kaalia Ustaad, one the most renowned guy for Radiators in RWP (Chah Sultan). HE got so many in stocks. Here is the details of his nos.
0345-5144382
0345-5381440
0300-5546201
If he didn;t ahve any then contact Raaz Khan @ 0300-9553066 (give my reference, ask him Adeel nain bhaija hay) & he'll get one for you in comparatively good price.