Need Architectural Approach For The Project

Question

We are preparing a new project and analysing various approaches.
There are multiple things where final output is dependant.  data flow of the project will be like following.
1. Data will be provided in comma separated file.
2. Raw Data will be stored in staging table.
3. Stored procedures will spread required data in other appropriate tables. (SP will be executed on staging table to extract data.)
4. Once data is available in table, (e.g. Address column) List of addresses will be taken out.
5. These addresses will be validated against UNIQUE ADDRESS WCF Service.
6. This SERVICE will provide some data.
7. Date returned by WCF service will be used by Web application to showi it on UI.
Now I want to make sure all the processing should be in sequence or no processing.
Initial thought is to use workflow based application.
Can anyone let me know other approaches? or any other simple way of doing it.

What are the free workflows that I can use, if finally I decide to use workflow based application?
Technologies
<< I am using C#, asp.net , Oracle/Sql Server/ WCF>>