Hi Christine,
That's an issue with tweetmeme. It should pick up the blog title. Not sure why it doesn't. You can change your settings for tweetmeme, so you'll have a chance to edit the tweet before posting it.
Click on the number count above "retweet" button, then your name at the top right corner, then on "My Profile".... or go directly here
http://my.tweetmeme.com/profile and set "Edit Tweets" to ON.
it's actually better to always review your tweets before posting, as you could add your commentary and appropriate hashtags.