Most likely you will need to work with the Public Defender. However, you may check with your local bar association and see if they can refer you to anyone. A word of caution: criminal matters are complex and often require quite a bit of work. It may not be easy to find a lawyer looking to do all of this for free.
Disclaimer: This Post does NOT constitute legal advice and does NOT create an attorney-client relationship. Do not act, fail to act or otherwise rely on this Post. Consult a licensed attorney in your jurisdiction.
I would agree with the prior answer, it is unlikely anyone will undertake the risk and difficulty of a criminal case for free. If your husband thinks that lawyer is not properly representing him, he can hire his own lawyer, or possibly ask the judge to assign a new lawyer, but that may be difficult.
I don't practice in Texas, and so cannot provide legal advice on this matter. This response is only for informational purposes.
The information that you have been provided in the previous two answers is sound and correct. If you cannot afford to hire an attorney of your own choosing you are going to have to learn to work with the appointed attorney. While it may be possible to find an attorney who accepts pro bono cases through the local bar association, I would not expect that you are going to find any, or very, very few attorneys who are willing to take on a case for free. I think that your husband would probably be well advised to listen to the attorney he currently has and heed his or her advice; to be candid, probation agents do not usually try to send someone to prison for a non-existent probation violation. I think he, and you, should probably take a close look at the petition alleging a violation of probation; I suspect that there are one or more terms or conditions of probation that your husband has violated.
If you're not happy with your court appointed attorney, the only way around this problem is to hire an attorney.
Please feel free to call me and we'll see how we can help.
Jeremiah D. Williams