Even when you do not mention in detail what type of financial calculations you need, I'm sure I an help you with it. I am an IT engineer with Post-Grade in Finances and I work exclusively with MS-Office solutions (Excel and Outlook).
I have practical experience in Finances, including Currencies, stocks, bonds and futures market, mortgages, pension funds, etc. Since, I worked for several years for a Stock Broker as Software Engineer, then I am sure we can complete whatever automation you need with Excel and Finances.
Writing an integration with Excel is the best choice when you need automation, where you can have control over all spreadsheets and their functionality. This integration goes in Excel itself and not necessarily a Spreadsheet with formulas saved on it. This way, you handle all the financial functionality you need on any spreadsheet you use. This integration goes packaged in an .exe installer, so you can install it on any PC with Office 2010 or 2013. Anyhow, if you need any other type of automation within an Spreadsheet instead of Excel, then it can be done too. I will only try to give you all the options you have available to get your project done.
If you want I can send you some demos (no compromise) of previous works I have done before for MS-Office, including some Financial Automation for Stock Traders (downloading quotes from broker, organization in spreadsheet, custom calculations, etc.). Or you an also check my profile for reviews of previous works.
Joe.