Property website

I would like to create a website for Estate Agent but one that other people can input data themselves and upload their properties. Also I would like to be able to download say if I have a few properties on a page I could just down load it for display. I would like it to work like gumtree or loot or savilles website functions. I had already created zone123.co.uk but it is not sufficient and not good enough. It will require membership site so people can upload properties themselves but be secure enough so that there is filter for adult materials and also that i can control and delete and bar bad adverts.