old wordpress site needs migrating

my website was built by a company which has gone bust. I think it was built with a wordpress light version. I don't have login details but can see all the data through godaddy. Godaddy have said that I need to migrate that data to a newer version of wordpress but I don't know how to do that. I need help, as there are 30 yrs worth of photos on my site - i.e. 50GB of data. I can't afford to lose that.
Thanks,