Many bands are a stock design, go to a jewelry store and ask if they can find you another set the same or similar. They should be able to pull out a number of catalogs for you to look through to find your band - then you decide what kind/size of stones you want or can afford. If the store does not have catalogs for you to look through, then go find another store and keep going until you find what you want - have fun. Don't worry too much about the 4C's unless you are looking at diamonds that are 1/4ct or more - of course you don't want "frozen spit" diamonds (white and cloudy) which you can have even when they are diamond chips - your jeweler can show you the stones before they are set. I worked in a jewelry store for several years (out of state) so I know that it shouldn't be too difficult to match your current set (or something very similar) - the cost these days is in the gold but you could request your ring be cast in silver and plated in gold which will bring the cost down. You may even be able to have the gold from your current ring (if it is gold) used in your new ring.
You may need to find a privately owned jewelry store rather than one of the chains but I have had some great luck with the small stores over the years.
No need for guilt or stress, you are not being greedy, you are just trying to to replace your current worn and loved set with something similar that will last as long as your marriage.
Have fun shopping and good luck!