I am a trained actor with multiple certifications in stage combat using various weapons, and extensive experience both in fighting in and choreographing these types of scenes. I’ll second a lot of the advice received here.
First, what Montresor said about the blade. You want an epee, or the wider epee, which may be called that in the catalog, or alternatively a “musketeer” blade. Almost all of the swords I have at home are musketeers. They show up better on stage, they’re not substantially heavier than the more slender epee, and they stand up to abuse better than foils or flat saber-style blades (which break and/or nick easily).
Also what Montresor said about the choreographer. It is amazingly easy to hurt yourself, badly, if you’re doing stage combat without knowing what you’re doing. I know people who have broken bones by messing up moves or by losing their distance or making other errors. I personally knocked both myself and my partner unconscious once when I misjudged a head butt: my own fault, despite my years of experience. An amateur takes even a greater risk. If you don’t actually have a choreographer, I beg you to find one, and spend four weeks, two hours a day, seven days a week, minimum, working on the fight. Don’t just try to replicate what they did in the movie; some of it is easy, but some of it is hard, and won’t read on stage anyway. In addition, you need to have a fight call before every single performance where you run through the choreography to reinforce it in your mind: first at half speed, then again at “real” speed (which, in point of fact, is between two thirds and three quarters of what actual combat would be).
Also what GargoyleWB said about how far away the audience will be. Remember, what the weapon looks like to you in your hand, up close, has almost nothing to do with what it looks like to somebody sitting a dozen yards off. You can get away with a lot here, and it might actually be better to have an elegant but clean look to the sword, for the audience’s perspective. Personally, I thought the hilt in the movie was kind of ugly, all junky and crusty and stuff; if you put something like that on stage, it would look cheap and plastic to somebody in the audience. Better to have a polished silver basket hilt with a few swoops and swept quillons or whatever. It’ll look better. Trust me. And most importantly, you won’t have to worry about stuff falling off it during the fight and getting underfoot.
However, what some people have suggested about calling the SCA, I’m not sure that’s a good idea. The emphasis on those weapons is different from the emphasis on a stage implement. A really nice dress sword, for example, may not be appropriate for actual combat; it may fall apart after a couple of whacks, and the owner may not even want it to get scuffed up. There’s a difference between something that’s made to look nice hanging on your belt and something that’ll stand up to being banged around a few thousand times. Better to go straight to the specialized source and avoid complications.
In any event, Rule One = Safety. Everything else is so far down the priority list that there aren’t any other rules until six or seven. 
Obviously, I take this stuff pretty seriously and will be happy to address any other questions you or anyone else might have.