Please help need advise on tell work that i cant travel cos of little girl!!!?

hello im a tele-account manager and i work from home 3 days a week i olny do mon to wed because of childcare for my little girl who is 22 months old! since going back to work last aug we have had quartly meeting which are spread over 3 days and 2 nights away from home up to now they have been fairly local about an hrs drive no futher! and they have always been mon to wed but this time it is tue to thurs and in nottingham and i lve in chester not really sure what i can do or say to work as they are noe getting a bit funny with me cos i said i might not be able to go because of the distance i will be away from my little girl and i wont have the car at the time so if anything happens i have to rely on public transport! please help and advise me thank you in advance xx