This is my first post on this site, and I'm not even sure if what I'd like to do is possible.
Anyway I have 2 workbooks 1 named "invoices" the other named "summary". The invoices workbook has a new worksheet started for each new week, in worksheet 2 cell B1 there is a small formula =Sheet1!B1+1 to increase the invoice number by 1 and cell B2 there is also a formula =Sheet1!B2+7 to increase the weekending date by 7 days. There is also a formula in cell M1 =A1&" "&TEXT(B1,"000") that will be hidden to combine the values of cells A1 and A2 the result of which I'd like to use for the sheet name. When I use Move or Copy to create the worksheet 3 the formulas in B1 and B2 don't update to use Sheet2! and I have to do this manually. Is there a way to get this to update automatically because the person I'm designing these workbooks for isn't Excel experienced so would struggle to keep changing the formulas.

With the "summary" workbook the total from each invoice worksheet in cell J33 is copied into a separate cells along using ='[Barn Stores invoices - Copy.xlsx]Sheet1'!$J$33 from cell C1 to O1; again the problem arises that as I copy the formula across the row Sheet1 doesn't update to Sheet2 and so on (I understand that if Sheet2 and Sheet3 don't exist the formula shows an error).

Is there a way to get these workbooks to work as I want them using other formulas or maybe VBA or am I asking for the impossible?

I hope I've explained what I'd like in clearly enough and I thank everybody for their help in advance.