two options mate ,
hub adapters , but youy going to be looking at adding at least 15-20mm with the adapter , so that will have to be taken into account regards the offset of the wheel of choice ,
or , have your 4 stud flanges welded up , and then faced clean in a lathe , then re drilled for the pcd of choice , you will have to see if the outsidfe diameter of your flanges leave enough clearance for the new pcd reuired ,
any compotent engineering shop should be able to do either bud ,
fair play , tis easy to follow the crowds and stay with safe wheel choices ,
hence why im going the 5 stud route meself lol !
beef