What are decent expectations to work for US co. in Beijing?

Dear all, I have been sought to work for a US company in Beijing which is the leader in it's field related to equipment, used mostly in the meat industry. I have worked in China before for companies with high tech solutions with a lot of applications in meat and animal areas, which has given me a great understanding of the meat industry. I have known this company for some time and get on well with the main people involved there. I have top qualifications and great experience and would seem to be a solution to finding a way to navigate the market after the company has tried many things and it is looking for someone they can trust. The problem is the sector seems stagnant after some years of setting up, due to lack of government investment for the various players in that industry. The problem is that there always seems to be a hesitancy when it gets down salary. I am looking for a situation which would pay a good salary, moving expenses, commission, car and a good school, etc I have some Chinese language, as my wife is originally from China and having worked there, but I would like to improve this aspect. The job would entail running the sales and administration - basically deputy managing director type role, sharing work with the MD. I would be grateful if someone could give me a steer on this, so that I am not neither underselling nor overstating myself. I would like to propose a package, but worried that what the company is looking for is to have someone very cheaply but I need to consider the big move for myself and family to China if I am to make it a success. I am not quite mid 40's yet! - but need to make sure the company is coming in with a good offer. Many thanks Michael