Criterion have announced that the planned DLC packs won't be coming to PC, citing a "limited amount of resources" as the reason for the lack of PC support.
Posting on the
Need for Speed: Hot Pursuit forums
, Criterion dev EA Spenser said "unfortunately we will not be releasing Need for Speed Hot Pursuit PDLC for the PC. While we are certainly committed to providing the best possible game experience and ongoing support for our PC community, (as you have already noted) we have a limited amount of resources that makes it so that we are unable to deliver new content to all platforms."
Console owners will soon have the opportunity to buy the Super Sports pack which adds extra cars to the game, but it looks as though this and the selection of free cars the Criterion are adding for Christmas will both be unavailable on PC.
There might be some good news on the horizon, though. EA Spenser adds that "we sincerely apologize for any inconvenience, but on the positive side we do have more updates and content on the way for PC players--look for news very soon."