The Monster Invasion packs are how you get the cards. Each pack comes with exactly 9 cards unless there is an Infinite card in there then there would be 8.

In September 2011 a new design for the pack was printed starring the Eleventh Doctor and the Silence on the front with the word: EXTREME!

The third set was released in issue 32. It features the Doctor and the Tardis and says "Ultimate Collection." This set had only 6 cards per pack, 5 of which were rare cards and the other one was an ultra rare .