Estimating + Quotation-Invoicing system for small shop

I have a relatively simple project that entails two sections. It is a specialized estimating system that will allow the workers of a sheet metal fabrication shop to enter dimensions of specific types of sheet metal enclosures and ducts, and then have the program calculate amounts of sheet metal required, cost per unit dependent upon the gauge/thickness/type of the metal, and add in a factor for labour, and the option to add in a couple other variable factors per type of shape. (Imagine a series of duct shapes... a "Y"-shaped vent, a curved right-angle bend, a reducing channel... all fairly standard shapes in the HVAC industry. However, a contractor will bring in specific dimensions, usually in inches, of how large the openings will be, how wide, tall and deep a component will be, etc. THERE is where the dimensions need to be entered into a subprogram for each type of shape, then the factors calculated to come up with a final cost.) See the attached PDF document for additional data that will clarify what the shop currently runs with, and what is required. The above mentioned part is relatively easy, actually, and I would do it myself in Excel, except the resultant quote results (and this is the second part of the project) must be stored in a format that can be brought over into a quotation/invoicing structure that can be stored like any typical sales/estimating/quoting system. The girl at the front of the shop must be able to bring up the data in its quoted form, confirm with the customer all the details, then save that as a customer order and later, an invoice that will be stored. Typical post-processing, in terms of end-of-month sales reporting, lookups, etc., must be possible from such a system. Either side of this type of processing is not terribly difficult; however, I have been unable to find a commercial package that will do such a task relatively economically... the ones who CAN do the estimating part are massive, expensive programs with long learning curves, offering so many features that the needed estimation part is less than a tenth of all that is offered; hence, much of the remaining application is never used and wasted. Companies with estimating/quoting/records-retrieval systems are a dime-a-dozen, but cannot do the variable-shape-dimensioning type of quoting required. Try to think of the finished product as a typical, relatively simple, quoting/invoicing/AR/AP, the kind that an experienced ACCESS programmer probably already has lots of boilerplate code for. The only difference is that the product costs come in through the estimating section from the shop floor, and I would supply all the formulas for that to work, most likely in Excel format, so the existing, working formulas can be transferred wholesale into your developed product. I would have done the project myself, but two limiting factors apply: 1) My MS-Access knowledge is rusty... somewhere over 10 years old. I am, however, very experienced in Excel and a range of other applications. 2) I have several other projects on the go, some technical, some programming and some investment, that prevent me from applying the proper amount of time required to do this in a timely manner. I would hope a programming task such as this could be accomplished in less than a week or two, with follow-up adjustments as required. If it would take more than 3 or 4 weeks to complete the main body of programming, this may not be feasible. Please advise accordingly. I await your response. Please respond with any clarifications you require. Thank you for your consideration. W. Halyn