In season speed training

You shouldn't expect to get a lot faster in that period from any workouts you might choose to do (experience might allow you to race faster, though). 

Doing some intervals might buy you a little extra speed, but also come with a higher risk if you don't have the base for it.  Do a few short, harder efforts (not "all-out" sprints, especially on the run) if you like, but don't go crazy with them.  I would choose to do more of your hard efforts on the bike.  Save the harder running for next season.

Hello
you race up in my neck of the woods!  Mini mussel is a great sprint race. I did it too.
I agree with other poster that within this time frame you can't expect to see great improvements from training and you shouldn't push yourself into doing interval work too soon when you aren't used to it.
I'd suggest for the run, run on varied terrain (hills give you good strength) and put in a few strides on some of your flatter runs (20 to 30 seconds of a bit more effort with full easy jog/walk recovery between - NOT sprint as I agree with other poster).
With the bike - what's the race you're doing?  Is it Cayuga?  If so there is a SIGNIFICANT (OK huge) climb very early on and I'd make sure you get lots of practice riding hills.   A good workout is to ride on a rolling course and push the hills and recover on the downhills.  This will give you strength which will translate into speed, especially on the flatter sections. 

Have fun the rest of the season - I agree experience will help you get faster too - and then you can plan your winter focus to have a great race season next year