Well it is safe to take them together, yes. However, it does seem a little odd if the diagnosis is now Bipolar. I will tell you why: Generally a regular anti-depressant isn't given to people with Bipolar Disorder because it has a tendency to kick their mania into overdrive. However, this happens quite often because individuals with Bipolar don't go to the see the doctor when they're manic, just when the depression sets in. If the doc doesn't ask the right questions they can assume it's Major Depression and just prescribe the anti-depressant. When and if Bipolar is suspected it is usual to cease the anti-depressant and begin a mood stabilizer.
That said, there are a lot of anxiety disorders (OCD is one) that have depression and other mood symptoms. People with these disorders are generally prescribed an anti-depressant, but if that isn't doing the job for them it isn't unusual for for an adjunct mood stabilizer to be prescribed (like Depakote). They are taken in combination quite often, so I wouldn't worry about taking them together.
However, what I would worry about is the combination of meds that you are taking overall. They don't seem right to me for several reasons.
1) your age. Generally as we age we are more sensitive to meds, not less. Thus, less medications should be prescribed if possible.
2) the use of a stimulant with someone who has anxiety. ADD can be treated with non-stimulant medications. For someone with anxiety this is preferable.
3) the use of xanax for the general anxiety. This is a habit-forming medication with a long half-life. People can and do become addicted quite easily. Anxiety disorders are commonly treated with anti-depressants alone and with something like ativan (shorter half-life) as needed.
4) the anti-depressant you're on is a tricyclic. This older generation drug is second line treatment and should only be used if all first line treatment is ineffective (newer antidepressants like Zoloft, Prozac, etc have many fewer side effects and interactions.
Thus I would recommend getting a second opinion. While the use of anti-depressants and mood stabilizers together is common, the use of all of these drugs together is not.
Please let me know if you have any more questions.