My understanding is you can apply up to 28 days before the completion of two years in the UK on a spouse visa (I don't think you can include time spent in the UK on a fiancee visa)
I am not sure of the affect of absences from the UK on your eligibility for ILR, but it is something you have to bear in mind if you seek naturalisation a year later.
Have you taken the Knowledge of Language and Life test yet?
