What do i do when my soon to be in-laws tell us what we are doing is wrong?

my soon to be and i moved into an apartment together at the beginning of the year we are engaged and trying to decide the date to get married. our 1 year ann. is coming up next week... backtracking to the engagement we would be paying for the whole thing ourselves and not having that kind of money we thought it would be best to just go to the courthouse and get married. ok so we decided that it would be special to do it on our ann. when we told his parents they insisted we waited so that way his younger brother who is overseas could be there. the problem with that is it wont be for another year and we really don't want to wait that long. not to mention back to the money my parents who would love to help cant help us because they don't have the funds either. but his parents do but because we are living together before marriage they are throwing the religion card. i have never been that religious but i respect that they are but today they attacked my family and their way of living and it hurt. although i love him very much im starting to think that being together just isn't the right thing to do at this point. his dad is constantly attacking me and my way of living and my beliefs. can i get some outside opinions it would be very helpful. thank you.