First you gotta check if the routing is HSH or HSS compatible,
1. get a HSS pickguard ( second hand ones aplenty at GC- GUITAR CONNECTION at peninsular)- SGD 25-SGD 40
2. Get humbuckers ( Seymour duncan ones start at SGD99 if I'm not wrong , from Davis-peninsular)
3. Get your trusted tech to install the pickups (GC also can) , (SGD 50 onwards?)
Optional, you may wanna change the tone ports or what not too, but that may cost extra depending on ur tech.
Hope this helps,
Cheers