If you want to fix to the plaster board you can buy twister plaster board screws which is a plug that looks like a giant screw that is screwed straight into the board and then a screw that comes with the plug is then scewed into the plug
(this doesn't sound very clear does it!). These are great for curtain poles, lights, small tv brackets etc but for heavier items you can use a frame fixing which is a large plug and screw that bridges the cavity between the blocks and the paster board.
These fixings can be found over here in bulders merchants a lot cheaper than B&Q etc and are what we use on new housing in this country and are ideal becase the partments are built in much the same way as our houses
I hope this makes sense, Harvey