We had this similar dilemma last year Maria, ours were due to expire in Feb this year and we would not have been ok for our trip last August by the time we returned in September also I was going back in October on my own and did not want any kerfuffle at the airport...
So what we did was had our April trip and then renewed our passports...Do you know the passport office will carry over up to nine months left on your old passport on to your new one?
We did our application on line totaly fantastic service you can track your passports progress at each stage, like passport received, priocessing info, printing papers ready for despatch...
I sent ours beginning May to coincide with the 9 months left on them and they were back two weeks later...
We still sent them special delivery though to be on the safe side, highly recommend the online application...