You really haven't ridden very far yet. 2000 miles in the summer/fall last year? 1000 miles since March?

I disagree with SlowOlympian, in my view you have no base to speak of, yet. I'll typically spend about 12 hours on the bike each week during the base training period, which adds up to maybe 800 miles per month. But forget the miles and start measuring your training by duration and intensity.

Go back and read ericm979's advice, above. Forget about increasing average speed at this time. Do a lot of your riding in HR Z2 (you can google for how to set up your HR zones.) You'll feel you are going really slow - the top of z2 will be way below 170 - but that doesn't matter, over time your aerobic fitness will improve. Joe Friel, in his training bible, suggests that before starting to develop a training programme along the lines he suggests, a new cyclist should just ride their bike steadily for a year. And since you mention aiming for racing next year, you have time to build up to it gradually.