Post Slider Custom Field Filter

I am using the Post Slider to display a custom post type. The CPT has 3 fields that I am trying to filter on using the Custom Field Filter. Two of the fields are dates, ad_start_date and ad_end_date which need to be compared to the current date. The third is a field which needs to be compared to the current page (this slider is going into a header, so it could appear on any page in the site). Is it possible to do this? I suspect I need some sort of globals for current date and current page, but am not sure of the syntax to use to insert them.

Thanks for your help!