I'm 43 and also went through several years of the Clomid/IUI thing, so I completely understand your pain. There are many causes to infertility, and many times, there are several issues going on at once. If the issue is just the quality of your eggs, then a donor would be a good solution. If there is another underlying issue, such as implantation problems, fibroids, endometrosis, high rate of miscarriage, etc, etc, then you may be likely to have the same chances of sucess with a donor egg as with one of your own. Talk to your doctor.
By the way, you can also adopt donor embyros (left over from another couple's IVF cycle), so that may also be an option. Nightlight Adoptions in California has a Snowflake embryo program http://www.nightlight.org/snowflakefaqsgp.htm
as does Bethany Adoptions http://www.bethany.org/A55798/bethanyWWW.nsf/0/1CA1884225...
As for me, after my last miscarriage, we are now looking into domestic adoption.
Good luck! If you want it badly enough, you will build your family one way or another! :)