Microsoft Flight Simulator 2004 or X should do. Depends on your computer hardware for which one to go. This in combination with the Dodosim 206 addon is what I used to prepare the CVFR/IFR part of the CPL and it helped me quite a lot.
To go even further you could have a look at TrackIR with a Radeon Eyefinity 3 monitor setup plus the new Logitech G940 flight system.
Could safe you some hours in the real helo or sim
