heli_spy has hit the nail on the head, it is not a simple crossover and it will cost a not inconsiderable amount of money. The going rate as an instructor around £40 per/hour (i may be a bit out of date) and that is just the flying hour, briefing and de-briefing take about 1 1/2 hours for a 45 min flight, so i'm sure you can see it's a long day if you want to make a decent living. However if your doing it part time and for fun and have another job that pays the bills then it can be quite entertaining.
Good luck
