I have to agree with Jim and Ron on this one. Even though photographers can take beautiful portraits of you, it takes a special photographer to be able to take a headshot.
Your headshot is supposed to be selling a product, you. You need to be the focus, you need to be well lit, nothing in the composition of the headshot should distract from you. If there are other elements in the image, it should be leading the viewers eyes to you, more specifically to your eyes because they are integral to showing the viewer who you are.
Take your first image, for example. Here are a few reasons why it doesn't work:
1. Distractions: There's a pole coming out of your head, in some areas the background is blown out (very white with no detail) and in other areas of the image there are lots of trees. On your person, there's a bobby pin sticking out of your hair, you're wearing earrings, a necklace (that's cut off) and a yellow shirt under your cardigan that is also distracting. Take a look at Jim's website (http://jimlafferty.com). His images have nothing in the composition that distracts from the actor. The actor is not competing with other elements in the image for the viewer's attention.
2. Inconsistent Lighting: The lighting is spotty on your face. You have a bright spot on your hair and on your nose. The overhead lighting makes your eyes appear dark. You have beautiful brown eyes and we can't even see them. In a good headshot the light should be kicked into your eyes to to give them a sparkle. The lighting here does you no justice. In Ron and Jim's headshots, the actors' eyes sparkle. You can see the life in them, you can connect with them.
You get the idea. I'm a headshot photographer and some of my best friends are photographers, but I would never ask them to shoot my headshot (without a lot coaching). Why? Because they take amazing portraits, wedding pictures, landscapes and night shots. They're concern is to make a beautifully composed image, not capture the essence of me.
Take a few hours (or days) to browse the headshot photographers on Reproductions.com or on lacasting.com. You'll be able to spot what makes a great headshot.
I was once a photographer doing headshots for free for theatre students at Cypress College and Cerritos College. Cypress College, Fullerton College, CSUF, CSULB and LBCC all have photography departments. Photographers always needs subjects, but not too many know how to shoot a headshot. For me, it took a good 6 months or shooting for free to finally get over taking pretty portraits and to finally capture an actor's essence. If you find a photographer who you click with and would be willing to work with you, educate them before they shoot you. Talk about what you want, show them images from other headshot photographers and make sure they understand that they are not taking a pretty portrait.
Great headshots don't have to cost a bundle. I know you're concerned about money, but please, please, please don't go cheap on your headshots. When you're ready to pay, pay for the best. One good job will pay for your headshots (including your reproductions.) Going cheap may be more expensive in the long run. You pay the gas to get to the photographer's studio, for a makeup artist, the session fee, you might have even skipped out on a day of work just to shoot with the cheapo photog. If your pictures suck, not only have you wasted all that money (and time), but you've got to pay out even more money for a good photographer. Do it once and do it right.
Good luck! I'm very close to the photography department at Cypress College, send me a message if you would like to know who to contact in order to find a photographer who will shoot you for fee.