There are certain things I think of when I think of Greek/Mediterranean food: mint, tomatoes, olives, hummus, lamb, fish. Grilling is a big part of the cooking technique because of the location, and no one wants to be slaving over a hot stove, so a lot of things are very fresh & crisp.
That said, no grill, no problem. There are a few things you can do with your protein:
One, if you want to do a "grilled" chicken, you can always bake the chicken, and then use a cast iron pan (because they get super hot) to char the chicken a little for the "grilled" flavor - you definitely have to watch it. (I also have a cast iron grill pan for my stovetop).
Two, if it's still cold enough, a lamb roast would be lovely! I really love lamb. You can spice it with rosemary, thyme, mint, then make a mint pesto to go with it.
Three, a whole roasted fish (or fish fillets). Think of a fish that's going to do well with fresh lemon and mint (not salmon). The bonus about fish is that it cooks quickly so you don't have to really cook for long when your guests are there. The problem with fish is that it can dry out in the blink of an eye.
Sides: Seriously, you can't go wrong with pita bread, hummus, and tabbouleh (use couscous if you can't find bulgur) or a Greek inspired quinoa salad with feta, olives, tomato, mint & parsley. Also, all of these things can be made a day or two ahead, so then you just have to plate it on the night of the dinner party, and I am all for being with the people you're serving.
I hope this was helpful, or at least gives you an idea of what you want.