I can't find any lenses for this camera. I have a Tamron 200mm Telephoto lense that fits on but won't lock into place.
If anyone can point me in the right direction, that would be great!!
eBay is your best bet. There is a small but comprehensive range of lenses for this camera series (AF200/230/270/300), ranging from the AF 24mm, 28mm, 50mm primes to the 28-70, 35-70, 35-105, 70-210 AF zooms, and the relatively rare 80-200 AF zoom. Some of the zooms come also in 'powerzoom' versions, designed for later bodies like the AF300.
There's also an AF 60mm macro, and a x1.6 AF converter, which allows manual focus C/Y bayonet lenses to be mounted on a Yashica AF body, and used in autofocus mode, with (obviously) a 1.6 multiplication factor on the focal length. I often use my CZ Sonnar 135/2.8 on a YAF body using this converter. Finally, there's an AF macro extension ring, the MA-8.5, for use with YAF lenses at close range.
For flash, there is the CS250 AF flashgun, designed to work with all the YAF bodies. The built-in or pop-up flash units on YAF cameras have a poor reliability record, but the CS250 is very good, and I also use it on my Canon G9, as the power output can be varied manually down to 1/16.
I have seen Sigma lenses with YAF fitting, but I do not have any, so can't vouch for their performance. However, I do have all of the Yashica AF lenses. They are better performers than I'd expected, coming as I do to Yashica AF from the ML manual focus range. The range of YAF lenses may be more limited than the ML manual focus cousins, they do cover almost every likely photo situation. It was marketing and pricing that did for the YAF range, not functionality and specification.
Alex