In my experience they will already have set a music budget - and it's almost certainly less than you'd like! So you don't really do yourself any favours by going in high and being beaten down!
My usual approach is to talk to the producer directly ( in a sort of matey 'we're all industry professionals here' way!) and ask what budget they have for music.
Any producer worth his or her salt will think quickly and tell you that's it's a half or two thirds of the actual figure, so you suck your teeth a bit in a friendly way and eventually you'll get what the budget was in the first place - and everyone will be happy, and they'll remember you as an easy to deal with composer and ring you next time.
Barrie's advice is very good, and that's the approach I've found to work well too. A serious producer who treats his composer with respect is a good contact to have, so if you show you are willing to negotiate that is a good basis to build the relationship.
Budgets vary quite a bit though and money is perhaps not the only thing to consider. Some projects are creatively very satisfying and good experience/good for your resume, or simply "a foot in the door". OTOH there are the cases where people exploit musicians' desire to work and try to get music cheaply. so sometimes you need to stick to your guns and be a bit stubborn about fees. When starting out this is hard to judge, it's a bit easier when you have some experience. Funny thing is, when I started out I was generally always happy with the money offered- I think I was just amazed to get paid for making music ;-)!
Be sure to join ASCAP or BMI as a composer and publisher. Try hard to retain publishing rights which is more and more difficult as production companies sometimes want to "own" the music. Register your titles and make sure the producers send in appropriate cue sheets.
I'm still getting decent quarterly checks for national TV music I wrote years ago.
area of broadcast may help you narrow it down a little...regional? national? i'd shoot for retaining publishing if at all possible, and 4-8k usd (i know, that's a broad swath) if its national. sorry, i really don't have much experience with episode packages. my closest experience is a cable 30 sec show open for 3k...so ask for at least that!
Ah, because the OP didn't mention publishing, I didn't, but trying to hang on to it is a must if you can without annoying anyone.
Here in the UK it's gone from the publishing being understood to be yours to an assumption that the publishing will be shared 50/50 with the production company in the space of a few years.
My (semi) jokey response has been, on occasions, "You want 50 per cent of the publishing? You'd better write 50 per cent of the music then!"
(P.S. I don't advise using this line unless you know the producer very well..)
I clearly don't have all the parameters here so I don't know how big of a project it will be, but 400$ CAD doesn't seem quite much to me!!! 400$ CAD is only 250€ which is less than what I usually charge for one minute of composition.