Welcome to the world of watch restoration. As you will soon find out, in most cases the cost of the project will likely exceed the value of the watch. Thats o.k. as long as you are having fun.
To find the crown you need the case reference number. This should be relatively straight forward. As far as the dial - Omega had many dial variations, so the only way to find out would be to search the web and reference books for similar examples (based on the ref number) and try to determine which might have been an original design. Even if you are able to find a design the looks original, the chances of finding an original correct dial are close to zero. That is why the condition of the dial plays so a major factor in the vintage watch world. In most cases, the chances of finding and original examples are low. Personally, I think your dial is in o.k. condition and will likely benefit from a light cleaning by an expert.
As far as replacing the sweep hand- you need to find out the length of the replacement hand (which I am guessing should be 13.75mm for this ref) and look for one in rose gold finish. You might be able to locate that with a parts supplier or on eBAY.
