My employer filed H1B 6 months ago and got a 3 year visa, and will not file a H1B again.
-Then you have only choice is that you have to go outsdie US to get the h1 visa to come back with the new passport so that you can get the new I-94 with the duration of your h1 approval notice.
Can I extend my I-94 at the US-CA border if I pass the CA-US bridge?
-No unless you are a Canadian citizen.