Tool for invoices & ride registration

Project Description:
I want to have an app build that saves and retrieves entry's in google calendar. it's a must have that the locations are added to the item and that it returns round trip numbers, so that i can calculate my mileage (in kilometres) for tax reduction.
the other function of this tool is that i can mark my hours for invoicing.

but the most important function is that it can retrieve categorie (customer) based totals per month.
for more information contact me.