There are several ways thay you can get your hands on these Cards:
Play PVP
Playing a lot of PvP in WWE SuperCard: Season 4 is a good way to gain enough CP to puchase one of these new Cards from the CP store.
Keep Grinding
The ladder rewards and draft pick boards have been updated to account for the three new card tiers, as has the Road to Glory mode. If keep playing regularly you will eventually reach these new Cards.
Credits
In WWE SuperCard: Season 4 you can spend Credits which you have either earned or purchased using real money on a wide variety of different card packs that unlike the game's rewards are not linked to your current tier. This means you could be lucky and pick up one of these new Cards in a pack.