Wordpress customization (create dynamic filters to categories with products) -- 2

I have a wordpress website that has a price comparison script and there are many products, categories and filters. Each category has as children sub-categories or products. For example, the category "TVs" has as sub-categories "3D TVs", "TV remote controls" etc., and the sub-category "3D TVs" has specific related products such as "LG 5D TV 42'". The problem is that the filters are fixed for each product and each category. I would like to have dynamic filters as they appear in [login to view URL] built in [login to view URL] and without deteriorating the performance of the website a lot, since there are more than 100.000 unique products and about a million products. The filters should be applied only in the categories that have products as their children, so that the visitors could find easily their products according to their attributes. The filters of course should be relevant to the specific product category. For example, if they are seeking for TV's, they should have as filters the manufacturers, the screen size etc. So I am looking for an easy way (either in the database or in the admin panel) that these filter attributes can be applied for each category with products as children. Thank you.