Designer Non-Responsive! Help!

I had my blog designed about 6 months ago. I love the design; however, I want to add some things, change a few things ... nothing major. I've contacted my designer in the past to make a few changes and she takes EONS to respond. Most recently, I've contacted her several times in order to get an estimate for some design updates and she completely ignores my emails. When I call, my experience is I rarely get a person, just a machine.

I'm very frustrated! Is there any way I could hire another designer to make some changes (add a Navigation Bar, make some column changes, etc.) I don't know how that works. I'm not sure if a designer would make changes to a blog they didn't originally design. I'm going crazy because I feel like I'm being held hostage!

Any insights or suggestions??? Thanks!