HIM help

Strength training can be incorporated into your regular workouts wherever you can fit it in. If that means dropping one workout or two a week to do it then that is what you do. You should be able to get two sets of training for 30-40 minutes a week in though and that could help though you may not see to much strength improvement before september. I am sure some of the more experienced lifters on here will have better advice. I would recommend, if you are not already doing it, lots of core work. A strong core will provide a very stable platform on which to build lean muscles.

as far as biking is concerned to get faster you simply need to ride more. If you do not have 4-6 hours to ride every week (or even more) consider taking your longest ride of the week and making it an interval workout in the middle. The use of intervals has seen some debate but it should help increase speed marginally as time goes by through training your body to work at a higher level. Again though the answer to getting faster on the bike comes down to riding more.

8% grade is fairly significant but not horrible. How long does this grade last for? My guess is it is a very short section but if it last for a while there is no shame in walking your bike up it. You will save energy, decrease the chance of falling due to instability at lower speeds, and possibly even get up the hill faster.

For finish times pull up last years race results and look at them. It should give you a good idea of where most people land and who the slowest finisher was. As long as you are staying within your own race goals (training, nutrition, and hydration) you should be fine. Check with the Race Director or the group conducting the race to determine if there are cut off times to be weary of in case you are worried. Good luck, keep training, and be confident in YOUR abilities. Don't worry about anyone else on the course.

Welcome to BT!

You don't need "strength".  You need endurance.  The best way to get that is to swim, bike & run.  If you are getting as much of those as you can manage and still have time (and can handle) some strength training, then you might consider adding it.  But if your legs are already having trouble "keeping up", adding more work for them is probably not the answer.

A decent time for a HIM is all relative.  Check out the results for your race from last year (yes, I think that's a relatively tough course) to get an idea.

You get faster on the bike by riding more.  It's always a challenge to balance 3 sports, but you should focus on your weaknesses.  Sounds like you should bike more (relatively speaking vs. swim & run).

8% is a pretty steep.  Not crazy-steep, but will require some solid work to get up.  How bad it really is depends on how long it is.  8% means for every 100ft. you travel horizontally, you are climbing 8ft. vertically.  If the hill is 1/4mi long, not so bad.  If the hill is 6mi long, welcome to the Tour de France. 

I would STRONGLY recommend against that tactic.  Strength sessions are the first ones to get dropped from a training plan if you can't fit them in due to either time or recovery constraints.

And nothing wrong with adding some core workouts, but your core should get plenty of work from "just" swimming, biking and running too.

I would agree with that. I do not recommend strength work. Right now I don't even do it. However the OP was asking how to fit it in because they want to add it so I was addressing that. It is not the best, or even a good way to fit it in, but if that is part of their goal it is a way to achieve it. I will stand by adding in 2-4 session of 15-20 minutes of solid core work a week though. I find that it helps tremendously to not solely rely on the SBR only for it and I am able to get some balance in especially as a new Triathlete like me.