Extract jobs from job pages to create an excel database

The objective of the project is to gain an accurate record of jobs that are being advertised in the sector I work in. To compile and keep an ongoing record so I can asses salaries, role tiles etc on an ongoing basis.

I need somebody who is able to build an automated system that will extract information from a number of web pages/jobs pages. Ideally I would like the ability to be able to add new webpages to extract jobs from.
The information extracted will be active live jobs that have been advertised. The information needs to include:

Employer Name
Job Title
Salary
Location of Employer if possible
Contact information
Other useful information if possible

The information could be put into excel or another easy to use programme.
I will need the information extracted once a week and ideally I would like the system automated.
I would like duplicate records checked for and deleted.