You are in an ideal area to get this done if you are in LA. We had a professional video done a few months ago and it turned out very nicely. The price does go up quick though soon as you get into having something truly look professional and not look like it was done by students.
It was a fun experience for us. We hired a producer that put everything together. The steps were.
1. Go over the script layout.
2. Put out a casting call.
3. Rent a casting room and have about 75 people come in and read over the course of the day to find the right pair of actors.
4. Find a good studio to shoot in with a minimal crew.
5. Shoot the video in 1 day in the studio
6. Start working on edits to find what we like as well as make a few different versions for split testing. The producer and his editor took care of the work here.
The producer took care of everything and we pretty much just had to decide what we wanted and did/didn't like.
The one step we wanted to skip at first and our producer convinced us not was a full day on casting. We really pictured hiring someone from a clip/profile more then having people come in all day to audition since we didn't want to rent the casting studio for the day. But he stressed how bad an idea that is and how likely it is we will end up with an actor on the day of the shoot we don't like and not much to do about it. In hindsight he was VERY right, we sat through tons of actors that had great clips but did not fit what we needed AT ALL. If we hadn't done the day of casting we certainly wouldn't have found what we were looking for.
It really comes down to if you are trying to spend sub $1000 and have something without a professional look or spring for a bit more money to make something that looks more like a national commercial that's filmed with proper lighting and sound ect.
I really can't stress how big the difference is on your final product and conversions on what your selling with a crappy video vs. something that is done in a studio with proper lighting and sound.