We recently purchased a wooden buffet oboe and the reeds that I usually use to play slide to easily in the top affecting tone. We were given a free oboe reed with a thicker cork but the sound of it is worse than those I have become used to...

Does anyone know a type of reed that I could purchase or a possible solution to my problem?

Try wrapping the cork with teflon plumber's tape. Shouldn't take much, & works well.

Well, for one thing, the reed is most likely machine-made--I'd be surprised if it weren't. Machine-made reeds are often terrible.

Some Suggestions:

Make your own reeds, unless you haven't been playing long enough to try that.

Buy some from companies that make hand-made oboe reeds. They are usually much better, but depending on the maker, may need some adjusting. If you have a teacher or know how to use a knife then you can make those adjustments.

If your reeds are handmade, when you place your next order tell the maker your problem and they should be able to offer real cork staples or o-ring staples that would solve your problem.

Be warned... the thicker cork staples can fit into your old oboe, snugly, but they will compress to the size of your current reed corks if you continually use them with your old oboe.

If you don't buy handmade reeds go here and have fun:
http://www.oboeinsight.com/stories/storyReader$449

That's a typical problem from oboe to oboe. Some of the corks I have are too tight for my oboe, some are too loose. In comparison to my oboe professor's oboe, she has to apply the plummers tape - or oftentimes she wets cigarette paper and wraps it on there because of how thin, but effective it is - to just about every reed she makes. But if I get a reed from her, she usually ends up having to take the extra material back off because the sizes are slightly different.
Hopefully you're playing on handmade reeds, and if it's by someone you know then I'm sure they can make the adjustments needed.
But the suggestion for plummers tape is a very good one and many people use it.

Here's what I'm going to say. I will repeat it 3 times. MAKE YOUR OWN REEDS. MAKE YOUR OWN REEDS. MAKE YOUR OWN REEDS. Making reeds that are playable (not perfected) is not a difficult task. Just use the staples you already have that are the right size.
alex