Just keep plugging away and be patient. The new cards will be coming but the Splinterlands team, as the post indicates, has never experienced such crazy growth. They are absolutely re-thinking their numbers strategies for how many cards and card packs they will be creating for the different things. The Splinterlands team is very good at being thoughtful of now only right now but the future. It would be a shame to have all of the card packs sold in 2 or 3 months. It would be fantastic financially but it won't lead to much long-term success of the game I don't think.
Best advice is just try to win what you can, keep that DEC as much as you can and try to buy the reward variety cards. The reward ones will be the cheapest ones you can find.