I would go in and explain to them what you just explained to us. Since your budget is fairly low, and it sounds like you have never ridden one before, tell them that you would like to test ride an entry level road bike and a price comparable hybrid to see which you like better.

If you are leaning toward a road bike and expect to ride on a lot of hills, you probably should look for a compact or a tripple. I would go with the compact myself, but you may want to ask them for recomendations. I'm not really sure how hilly it is where you live.

Be sure to ask them about the differences between the components on the different models that they show you and make sure that they explain things to you in a manner that you can understand.

If you don't understand what they are telling you, feel free to ask here. Also, if you don't get a good vibe from the shop, try another one. You should feel like they want to answer your questions and help you buy the right bike without too much pressure.