From the version 1.7.7 the plugin contains own Search Field that can be added in Filters widget and allows you to search through fitlered posts. Please, see demo example.
It supports search in post content, posts title and SKU field in Woo products. Also it is fully compatible with filters, supports AJAX, dynamic recounts etc.
How to use?
Just enable appropriate checkbox in Filter Set setttings and optionally set field’s title and placeholder.
Also you can specify field’s position in filters list, usually it is top position.