Sorry, the 810 is another example of the cheap Dell printer, which is a host-based printer. Even if there is a Lexmark counterpart, that doesn't mean that the Lexmark driver will work - Dell often has custom system boards in their printers.
Oh yes, Host-based means Windows-only. Most people have poor luck with Dell printers on OS X.
So, even if there was a Lexmark driver, it would still be for Windows-only.
For better results, try a more mainstream printer, such as Epson, HP or Canon. Well, just my .02€ on that.