Sydney so you're basically in a full relationship with your long term boyfriend and you both hope to marry.
Unless you can convince the elders you won't continue to fornicate and you will marry asap, cash strapped or not, it looks like you will be DF. However weddings cost the price of the marriage licence, money isn't necessary. You can have your wedding celebration once you've saved up (maybe as a 'blessing' or renewal of vows etc).
I think that's the only way around this if you don't want to be DF and/or leave the religion. It's more likely - as others have said - you will have the 90 dAy DF.
You haven't said if you have witness family. In my experience this will also affect how they treat you. They're harsher if they have you by the short and curlies with a witness family to loose!