I personally think the more your ride the stronger you become the faster you will go with time. Embrace where you are currently and set a reasonable goal for the week, month, and/or year.

I would also second, third, fourth the suggestions to ride with a group. Having someone to chase is a great motivational tool. I will often pick a group to follow, knowing I won't be able to ride with them for long. However, knowing they are out in front keeps me pumping away as I cruise along. Of course, see others ahead of me also gives me the drive to pick up the pace in an attempt to catch them and better yet pass them if at all possible (I'm a tad bit competitive).

Finally, don't get down on yourself - enjoy your time on your bike and remind yourself of the progress you have made thus far. Again, write down some goals, post them, review them and go for them.

Good luck and enjoy yourself!