If you are at all handy they are not hard to install yourself.
You remove the grill which by pulling it down. A bend paper clip may make this easier. Under the grill will be four screws that hold clamps against the ceiling. You can remove the screws completely. A powered screw driver makes this easier.
The speaker will tend to fall when you get two of the screws out so hold it in place,
After you remove it you can measure the diameter of the hole and get a replacement speaker that will fit. Many brands to chose from. You might want to upgrade them to better quality speakers since it's your room. You can get them from Best Buy, Costco, all AV custom installers, and audio stores.
If you don't want to deal with it at all call a local AV...