Change this single drop down to two drop downs? (custom post type search bar)

How can I change this search bar drop down, which displays everything, including child categories, in one long list, to two drop downs? I need one to select state and the other to select city. I’m afraid one list will be too long. The below code is greek to me…

<button class="btn-topsearch" type="submit" tabindex="3"
title="<?php _e( 'Search Ads', APP_TD ); ?>" id="go" value="search"
name="sa"><?php _e( 'Search Ads', APP_TD ); ?></button>

	<?php wp_dropdown_categories('show_option_all='. __( 'All Categories',
APP_TD ) .'&hierarchical='. $cp_options->cat_hierarchy .'&hide_empty='.
$cp_options->cat_hide_empty .'&depth='. $cp_options->search_depth .'
&show_count='. $cp_options->cat_count .'&pad_counts='. $cp_options->cat_
count.'&orderby=name&title_li=&use_desc_for_title=1&tab_index=2
&name=scat&selected='.cp_get_search_catid().'&class=searchbar&taxonomy=
'.APP_TAX_CAT); ?>