I looked at the trek website, and the 7300 is a couple steps above "entry-level".

I've ridden hybrids, MTBs and road bikes. Yes the road bike is faster, but it's not 10mph faster, not even 5mph (for long rides) in my experience.

If you want to make your bike lighter, try getting a standard saddle instead of the heavily cushioned thing with the springs.
Those cushy, sprung saddles weigh a lot.

But most importantly, get narrower tires. If you have the stock tires those are 700x38 and look semi-knobby. Try to get some slick 700x28s. It'll make a lot of difference by reducing weight where it really counts - the wheels. Easier to accelerate and climb with.

You can alter the handlebar setups in a number of ways to improve aerodynamics. Lower the stem, add some kind of aerodynamic clamp-on bar. Maybe even switch them out for drop handlebars.

But the main thing is that a heavier bike isn't going to be that big a deal unless you are climbing serious hills. And if you are riding around the park (Central?) there probably aren't too many big hills.

The above are just suggestions if you want to spare yourself the cost of buying another bike. My bikeshop has a bin of saddles for $5 each. And tires can be purchased for $10-$20 each if you shop around. All much cheaper than a new bike. Entry level bikes seem to start at $500 and go up dramatically.

I've found that the main reasons I can't keep up with people are:

1) Lack of conditioning
2) I'm overweight
3) I wasn't much of an athlete when I was young, and now I'm 45, fer gawdsakes.