Private renting & UC

Hi, there's a flat come up for £1300- the LHA amount for 2 bedrooms. I'll be going back to work part time in September earning around £950 & I'm a single parent with one child on UC. Does anyone know roughly how much they'll pay towards my rent & how much my UC will be cut? I'm currently getting just over 600 for me and my child. I want to make sure I can afford the rent & cost of living if I go for this flat but UC won't give me any real answers. Anyone with any experience of this? Thanks