If you are new, it may take some time for the analytics, google and search engines to catch up.
 
It's always wise to promote yourself - set a FB page just for your artwork/paintings, maybe even a twitter account if you wish (never a bad idea to have your FB feed go to twitter - dislike it the other way 'round). Be sure to get your friends to Like your page & ask them to recommend to others. Your following will grow and your card sales will increase (hopefully!). The more places you are active, the better your chances are. It is helpful to be consistent naming your blog/FB page/storefront/Etsy store/Red Bubble/Zazzle - Consistent naming means you'll likely show up more in google searches.
 
I see you've started adding sentiments to them - this is a good idea particularly in the US. Explore other ways to incorporate them into the card. Look at other people's handling of composition and balance in terms of the words and typefaces. Keep uploading and make those key words count!  
Keep an eye on the GCU Blog as well as Corrie's excellent posts at http://gcucommunity.com  
 
Your cards and paintings are lovely. I wish you the most success!