Sorry to sound negative, but it sounds as if you're in a position where it will be difficult to make progress. The clerk should have a contract of employment. She should report to a group of councillors or possibly an individual councillor on everyday matters.
Although the clerk often reports to the chairman, it is important that the clerk maintains a degree of independence, and is responsible to the council as a whole, providing support to all councillors.
If the chairman is her husband, then he would plainly have a personal interest in anything to do with the clerk's employment. In that situation, the clerk should not report to him and he should not be involved in decisions to do with her employment.
The council can exert control over the clerk - but from what you say it is unlikely to act effectively in this case.
On major issues, public pressure can lead to councillor resignations, but for ongoing matters it's unlikely there will be enough interest to be effective. Otherwise, the only recourse is at election time, when you may well need some fresh blood in the shape of new candidates. The next time for electing parish councils is May 2015.
