Web crawler scrapping development tool

Hi!

I need to extract raw data from certain pages of sale of second-hand products and store in any structured storage (db better than csv).
Then we need to crawl it periodically to get new global copies of al the data to know the new products that people are selling, to get the changes in the existing products and to get notice of the ads that have been deleted (I understand that if an ad is removed is because the product has been sold, and i want to know it).
With this we could get the price evolution of certain types of products, grouping this information by the other fields that i extract from the product detail page.

There are some webs that we need to crawl and extract info.
One of this is http://www.agriaffaires.es/
There are several categories and subcategories. Just a subset of this have information that we need. But every categorie have, finally, a product detail page (like this http://www.agriaffaires.es/usado/tractores-agricolas/6105520/john-deere-7530-premium.html ) that has information in different fields about the product that they are selling.

for all this (the need to update this data periodically), i need the development of a tool that can do that installed in my own servers..

Could you develope some tool like this? (maybe using any of the frameworks that exists , like http://scrapy.org/ or ssoomething like this)

Thanks in advice