since you do not have a home theater receiver then you want to hook everything to the TV and then output the TV to the sony soundbar.
Since you gave absolutely no model numbers or information on how you have it connected I can not tell what kind of cables to use for each connection.
Ideally you should use HDMI from dvd player to TV, and toslink (also called optical and spdif) from TV to sound bar; where that will work with your application I don't know without more information.
There are also select few sound bars that do have hdmi in and out.