Thank you for getting back to us. 

Since your seven clean days have already been completed, and it is dangerous to walk to and from the mikveh in your area, you may immerse late in the afternoon before Yom Tov begins. After you have immersed, you and your husband should not see each other until after nightfall. You would need to call the mikveh in advance to find out if a late-afternoon immersion can be arranged.

Alternatively, you can drive with your husband to the mikveh before sunset, and walk back together at night, after you have immersed. It is acceptable for your husband to miss davening in shul to help you fulfill this mitzvah. You would light Yom Tov candles from an existing flame after you get home.

Please feel free to get back to us with any further questions. 

Moadim l'simcha!