We are sorry to hear of the challenges you are facing in getting to the mikveh. Reaching out to us is a positive first step in strengthening your mutual commitment to keeping taharat hamishpacha. We encourage you to contact a yoetzet in your community or on our hotline to discuss strategies that can help you lengthen the time you are permitted to each other. It is possible that you can get a valid hefsek and begin your seven clean days sooner, and there are additional medical and halachic approaches to consider.
When mikveh falls on Friday night and there is no local mikveh within walking distance, there is room to allow immersion late Friday afternoon, with enough time to make it home for candle lighting. Following the immersion, the couple should not see each other until after nightfall. The halachic supervisor of this site would permit an immersion late Friday afternoon in your specific case. You need to discuss this with the mikveh attendant in advance to arrange the logistics.
Regarding mikveh for this month: If you had marital relations during your period, you should still immerse, although your immersion will be delayed. You need to begin the five-day minimum again, with day 1 being the day you had relations. You should be able to do your hefsek on the fifth day, begin the seven clean days the following day, and then immerse in the mikveh at the conclusion of the seven clean days.
Please do not hesitate to reach out with any further questions.