@asad1019
I didn't notice you car 
Although head swap is just bolt on job, but remember that you have to remake the block internals otherwise you will end up in a problem.
Besides that, you need complete ECM + Wiring for the DOHC engine else the engine won't perform well. Although alteration in the existing wiring is also possible but then still you need to change the ECM.
If you need to upgrade to DOHC head, better buy a complete kabli engine and transfer parts to your engine. (The old parts dealer will rip you off if you buy just the head parts, telling you that the remaining parts are garbage for him)