Hi, I have extensive experience in Access within the investment banking industry and I also have two postgraduate qualifications so your project will be straightforward to implement.
I actually recently completed a similar project which tracked a company's estimates, jobs booked, timesheets, expenses, and invoicing, and with Outlook integration to send confirmation emails and invoices.
I specialize in making Access databases first class Windows applications so they're intuitive, aesthetic, and easy to use. Please see the portfolio section of my profile (accessible by clicking the Systems3000 link) for examples and reviews.
Migrating your current Excel setup to Access is also straightforward and will benefit from the advantages a relational database has to offer: i.e. accuracy, easy to enter and find information, and a user interface that models your business processes precisely and intuitively.
I can naturally provide incremental builds so you can offer your feedback on the development and modifications as it progresses.
Please let me know if I can be of assistance.