Common problem, Needy. To fix the holes, drill them out and glue in some dowels. Let the dowel stick out a bit. When the glue has gone off, saw it off flush.
You need for instance, 8mm dowels and an 8mm drill bit. When ready, mark where the screws gon and drill a 5mm hole. The existing screws should take nicely then.
5mm is standard. Check that this is what you have.........
Relocating the 35mm hinge hole is tricky without using a pillar drill or drill press. The bit mentioned by Talbot is the one, but it does have to be positioned accurately. Do this only if you really have to.