Modify an Opencart extension (Ajax Filters)

I have this module here that i need to make some modifications. [login to view URL] 1 - When i select Attribute filters, it only allow to select one attribute each time... We need to modify the modulo to allow select multiple attributes, for example to people be able to select to show both Core i5 and Core i3. 2 - Extend the module to create an radio option. For example, on an computer store you have several laptop versions with lots of memory options. We want to make an radio option to work like this: Option 1 - 1GB (it will show all latptop with memory 1 = 1GB of memory) Option 2 - 2GB (It will show all laptop with memory 2 = 2GB) Option 3 - 4GB or more (It will show all laptap with attribute memory bigger > 4)