Within the baracks menu of ♥♥♥♥ there is an unlock stats button. Clicking this button will grant you prestige 10 and level 70 with all chalenges completed (Includes camos, titles, emblems and attachments)

1) Whilst in the main menu open the console using the tilde key, then enter the commands:
*Setting Prestige:
/setplayerdata prestige x
x = ( 0-10 )

*Setting Rank:
/setplayerdata experience y
y = ( 0 - 2434700 )

Prestige 9 Level 70
/setplayerdata prestige 9
/setplayerdata experience 2434700

Click here to see experience values for each rank: http://callofduty.wikia.com/wiki/Call_of_Duty:_Modern_Warfare_2/Ranks