Create new module for open source PHP Cart software

I am currently working with opencart software v1.4.9.1 which I intend on using for my website. You can see a demo at [login to view URL] I have already made some changes whereby I have created a new module to display the parent categories in the header instead of the column on the left. I would now like someone to create a new module for me that would contain the features below: 1. The child categories to appear in the column on the left (with no child categories displayed if there are no child categories) - each category will have a checkbox next to it so a customer could select one or many child categories to filter products depending on what is selected 2. As well as categories, new filters to be created (with checkboxes so one or many could be selected) for size, colour, brand and material. The values for these filters would be based on the products selected eg, if womens tops were selected and filtered by short sleeve tops and we only had these in sizes 8-10 and 10-12 and the only colour available was red, these are the only values that would show. On the otherhand, if perfumes were selected, you might see 100ml, 200ml (but not 8-10 or 10-12). 3. Any filters used would be displayed in a seperate box at the top of the left hand column (with customers having the option to select any filters not yet selected)