Training for 10k

I have been running since January, my birthday. From Happy Run, I just kept joining 5k races, and of course, I never win. I started with 49 mins, now I am down to 40 mins. Yes, a big difference, but I feel that my speed is not picking up at all. I have joined the following:

Happy Run
DLS Run
Dare To Care
Doc Fit
Condura Run
Pinay In Action
Slimmerun

Only in Pinay In Action did I run from beginning to the end. So I am really a beginner in this kind of sport, but by God, I really love it. I get chills from watching people all running and trying to convince themsleves that they can do it, including me. I know I look kinda dumb running, but I don't really care. I feel like a child who is given a favorite toy....

Recently, I have made a decision to train not for speed but for endurance. I felt that I needed to challenge myself, and maybe, if I lengthen my distance, speed may just improve. Yesterday, I ran 6.6 k in UP, for about an hour. My husband said that's so slow, but I was really proud of myself, because I did not think I was going to last that long running, no walking at all. So I guess I can see baby steps in my improvement. I am just hoping my knees are strong enough for me to reach my goal...