I ran my 1st 5km in late December. I have now managed 10 miles on one occasion. My 5km was stuck for a few weeks until I started working on form and speed. Hill sessions have recently really helped to the point where this saturday I took a minute off my 5km time just like that, out of the blue. So keep at it. The time will improve eventually. Also bear in mind that more distance doesn't always equal better speed at shorter distances.
Maybe work on a quicker cadence (number of steps per minute) with a shorter stride (if you don't already). This will help you get used to moving your feet quickly without causing yourself an injury from over working. Then when you're ready you can work on lengthening your stride to cover more ground faster. But that's not important right now. But I do think a lot of beginners (I've only been running 6 months myself but am up to 18-20 miles a week), benefit a lot from working on their cadence and running 'lighter' on their feet.
I've used Endmondo on my Galaxy S2 phone since taking up running back in November. I have run in 5 Parkruns, in 2 locations, and the app had been absolutely spot on with the distance. Today I ran my first 15km and the route had a lot of sharp turns and doubling back on myself (I got a bit lost lol), and when I got back to PC to see my run on a map it was mapped perfectly. I am considering a GPS watch, but I am now not so sure because of expense.
I know the watches are easier to view when running but for me personally, I like to run without worrying about all that stuff. I just want to run, and find out later how far and fast I was. Less pressure that .way.