customize WP theme -- PHP: simple field type changes

I purchased an e-commerce WP Theme -- Market4. A product item currently offers only 2 drop-down list fields. [size & color]. I need more field types than what is currently available. These are the form fields that I need displayed in this order: Label: Type: (text field) Label: Material: (drop-down list) Label: Engraving: *(radio buttons yes / no) [default to no] Label: Font Style: (drop-down list) [hidden until 'yes' is selected for engraving] Label: Enter text to be engraved: (text-area field) [hidden until 'yes' is selected for engraving] * when the 'yes' button is clicked THEN the 'font style' & '...text to be engraved' fields display I believe this will be a change to 3 files and shouldn't take an experienced PHP coder much time at all.