Construction Cost and Footprint estimation

I have got a project on estimating construction cost and ecological footprint. I need to come out with a software programme using Visual Basic and MS Excel which could estimate both the construction cost and ecological footprint. I have a sample of the cost estimation programme done by someone using Visual Basic which could be used as a guideline on what the programme looks like. I have also an Excel model of the ecological footprint estimation. The two model have all the data and formula needed and what I need is to combine these two sample to produce a single programme with both functions and change the original layout. I will also provide all the data, sample and my layout of the program after the bidding.