your mum looks very photogenic.
why not just get a white sheet, drop that off the curtain rail. then borrow an off camera flash for your 450D or try working with natual light. there's loads you can do at home or just find a nice sunny day. get your back to the winter sun try some outdoor shots. make it into a mother, daughter picnic day out...although I'm sure lunch indoors would be better at the mo!