As above your times so far are looking good! I haven't got under a much under 7 mile yet but can run a 3:40 marathon. You will of course find you are better at some distances than others so some of your targets may feel easier than others. The only way to run faster is to run faster. I'm not trying to be clever but once a week just have a mess about with speed work (read up on fartleks). As Tricia says maybe go for a half in the autumn (Sept-Dec) and a 10k spring/summer that will get your speed work up together. Have a look at Hal Higdon's website, he has some good training programmes.
Also living with hills is a blessing in disguise as then any flat race will be a breeze!
Don't forget you can add lentils (especially red ones) to thicken up a sauce, sprinkle nuts and seeds on yogurt and peanut butter are also ideas that have worked for me as is hummus which is sesame and chickpeas so has your essential fats and protein.
(I have only been a veggie two and a bit years and have run marathons as meat eater and veggie and found no real difference to my ability).
I found just throwing in a bit of speed work made a difference.
So once a week, on say a 4 mile run....
Running my "normal pace" for a mile and then spending two miles running faster between say four lamp-posts then going back to "normal" again before speeding up over another random distance be it two roundabouts or to the next litter bin before spending a mile back at my "normal" to finish.
I have non-running friends who last October were puffing after half a mile. They then got to a point they were grumbling at running "12 miles this weekend" and by the end of it they were cheerily saying "ONLY 12 miles this weekend" They got around London in just under five and a half hours.