RITD will get another boost when it's certified diamond. 
But seriously, they'll be neck and neck for a while. PRA will hit 7M first. How much has their album sold? 500K? As of now close to 14M+ people own RITD. It will be harder for the single to shift large amounts of sales after it already is on 8M albums. 
Wait till X-Factor and Dancing with the Stars cme back. 
 
And they should had put the Grammy performance on iTunes. I got a rip on my iPod and it's magic. 

 That had to be one of or if not the best performance of it.