Your employer has to apply (and get) the WP3 at the Labor Dept. Then he can send you a proper scan so that you can upload it. This WP3 is valid only 30 days from issuance.
Surprised when I read: "my company has no clue about it"
Every serious Thai Company should have a clue about WP3
According to their website:" The E-visa process can take up to approximately 3-4 WEEKS, depending on the type of your visa and the completeness of your documents."