well i've always said do it yourself!
chrissi (my girlfriend) runs my own dj diary and it's the best thing we've ever done keeping things in-house (well we use a few agencies but no-one we rely on). now, 10 yrs into serious dj bookings, we decide exactly what we want to do and what we dont want to do. with agencies you don't have that freedom. plus, you're always scared that they're going to drop you.
i say forget it and put the effort into keeping everything under your own control. get a friend to run your diary, set up a agency name, pay him something like 10% ontop of your fee and off you go.
:)