Applicaiton programming - Real estate style transaction database

The objective is to build a desktop (or web based) application for capture and manipulation of transaction data (e.g. a real estate type database). Currently our company captures stores and manipulates these datasets manually and disparately using Microsoft excel. In an effort to improve efficiency and standardise the workflows we are looking to commission a software and database package that will simplify and streamline much of this work. The transaction data needs to be linked to the date of the transaction and linked to currency exchange rates, Company Share prices and commodity prices in real time (daily to monthly frequency). Data entry of these transactions needs to be interactive e.g. if the entity transacted is located in Australia but transacts in USD it can be entered as such, through drop down type data entry; if shares form part of the purchase price the ASX or NYSE etc company codes. (E.g. BHP) should be linked to call up the share price at the date of the transaction and a specified currency. All transaction $ and share value in $ are then converted to the desired currency or the current session as the final transaction $ price. Supporting evidence of these transactions e.g. PDF's of press releases or stock exchange announcements should also be stored and linked to the transaction. Analytical modules will allow sub-sets of the transaction data to be filtered and sorted, graphed and analysed with simple stats/graphs updating in sync with the results of the searches and filters and a specified session currency. All transaction data should be stored under a single unique Transaction ID (currently stored in a single row in excel) All data and in particular searches and filtered results should be exportable in at least a CSV format with 1 transaction per row and columns as the data fields. User permissions and levels to limit alteration of transactions once audited by senior staff (initially should be linked to company usernames and accounts through standard windows accounts). Design should be modular to allow for future addition of analytical packages, linking additional datasets, spatial modules i.e. location maps and search and filter via locational searches etc.