I've seen that you've also posted your question in the teaching adults forum. You'll probably get answers about sources of material from people using that forum, so I'll take a different approach.
It seems to me that a lot of the work you are doing is focused on fluency. At an advanced level, it can be useful to return to a focus on accuracy. Many students at this level still have problems formulating questions, so put the student into the role of interviewer as much as possible. Encourage him / her to use more elaborate questions such as ‘I was wondering if you knew about ....’. What you lose in terms of natural speaking, you gain in accuracy. You can also return to a focus on set phrases or functions for interrupting, repairing a breakdown in communication etc.
You and your student probably feel very comfortable speaking with each other and you’ve probably developed a style of speaking that is in a particular register and this is totally normal. To practise different registers, you could try role plays or any speaking activity which involves you as strangers at a conference, two mates down the pub etc.
Pronunciation can still be a problem at this level. Many advanced students have acquired the correct pronunciation of individual sounds but their connected speech can sound stilted or monotonous because of issues with stress and rhythm. The Headway series has some excellent supplementary books and cassettes for practising pronunciation.
In a more general sense, you can involve the student in the choice of topics and material that is covered. You might also want to reconsider your student’s needs and objectives. If you carried out a needs analysis at the beginning, it might not be the same at this stage. Your student’s needs could have evolved, through a change of job, change in life plans, etc. He or she might need focus on other skills now. So it would be a good idea to talk to him / her about this.