My employer has agreed to let me stay on and not make me decide about if I want the full time job or not until I go on maternity leave so I am very happy with that I can work there until I qualify for leave then tell them my decision that I don't want the full time job and still get maternity leave which means I won't have to find another job and it won't leave us in financial difficulties :)
I am very glad things worked out in the end, thanks for everyone's support and advive!