Business analyst needed

I need to write fully detailed requirements for planned system. The system is basically "inventory control/management" and online shopping engine. The requirements needed to be written from business point of view (not technical). What I need is fully detailed information as follows: - What such system needs to have as functionality - How does it suppose to look like (in terms of usability) - How many users the system suppose to handle - What type of customization the system need to handle - What type of information the system needs to provide to the end user. and so on... I'm not sure about the budget. You are welcome to post a bid what you think is right.