Virtuemart 3 Product Filter by Custom Fields - customization

[psm]

Dear all,
I would like to ask you, if you have some experiences with this extension? I bought it from this link:
http://myext.eu/en/vmcustom-param-vip?virtuemart_product_id=2&virtuemart_category_id=1

And I would like to change way how it shows results. Now it is showing results, just after click on button "Show". Is there any easy possibility how to change it for showing results immediatelly after one of parameters is choosen? Because first option is not very customer friendly solution. 

I am not expert in ajax.

I thought also about showing "Show" button on the bottom of product filter by setting postion: fixed. But it works just for whole page.

Please, can you advice me some way, how to change it?

Thanks,
psm