Race swimming and running help

Ok gang, here's the deal.   I finished my first Oly yesterday with my swimming and running being my worse events.   I trained hard and felt as if i was ready, but my splits for my swimming and running doesn't have alot to be desired.

First, with my swimming.   Last week i swam a mile in the pool in 32:53.   I really thought my swimming was going to be my best event and was thinking i might be able to get somewhere in the 31 or 32 minute split yesterday.   However, i run to the beach and my wife tells me my time was 41 minutes!!!   I was shocked and discouraged.   I was also a bit surprised because i caught a couple people from precious waves and numerous from my own wave.  Now, good news is that i believe i know where my problems are at.  

To start, i felt comfortable in the water with no anxiety....i love swimming open water.   When i got out of the water i was refreshed and felt great....so i didn't cook myself.   What i did do was swim all over the place and i had to constantly look up to redirect myself.    Looking back, i was looking up and breaking my stroke to get on course more than i was swimming.   I know this played a huge factor in my really slow split.   Also, it was my first swim in a large group of competitors (my wave had 68 swimers).   I should have started more in the back and to the side, but i got over confident and started more of the middle and got kicked around.   That played a small part too i think.  

However, i need advice on how to practice swimming more controlled and not zig zagging as i was doing.   Having to look up and sight constantly probably lost me nearly 10 minutes in time.    Is there something i can do to help improve that?

Now for my running.   Before the race, my previous long run was 8 miles i did at a 9:15 pace.  I did a couple bricks, but not enough (i'll do more from here on out).My split yesterday for the run was 1:06.   The run started great, did the first 5k in 28 minutes.  However, i got to mile 4 and literally hit a wall.   My pace dropped a couple minutes slower and i had to take a couple walk breaks.   The last mile and a half was pure torture for me.   My legs were just shot.   Funny thing is that my legs felt great initially after the bike.  They just broke at mile 4. 

So i'm wondering if just increasing my mileage is the way to improve my race running or should i be doing other type of training runs such as bricks.  How many miles for training should i do when training for an Oly?   Should i do interval training or bricks or what.   If i could just do the whole 10k like i did the first 5k yesterday, i would be very pleased.   Is there something in my training i need to change other than long runs?   How many miles should a long run entail when training for an Oly?

Sorry such a long post.   Got alot of things i want to work on and need some direction from those who have been there   I appreciate all the comments and advice.