What is the best way of getting additional house cards (like the ones that come in the core set). I recently made a second stark deck and realized i only have one house card to use. Do they only come in the core set?

You can buy 'em @ eaglecard.org

teamcovenant.com

and sometimes on eBay.

You can trade for them (or sometimes buy) @ TradeCardsOnline.com

Thanks so much!