st johns wort is a mao inhibitor and targets more then serotonin. do not take st johns wort and an SSRI togther, you run the risk of serotonin syndrome which can be fatal.
for occasional relief you can try kava kava, valerian and melatonin to help your sleep.
5-htp is a precursor to serotonin and again dont take it with paxil as serotonin syndrome can occur(you can, but consult with your doctor).
i can give you some help if you were off the drug, i just came off celexa fro GAD, and am treating it naturally somewhat effectively.
there are alot of supplements that can help but your limited to sedatives in all honesty because of the ssri.
my honest advice, and the best advice you will get is to undergo CBT(cognitive behavioural therapy). i highly doubt that anxiety disorders are chemically induced, more so produced through maladaptive learned habitual thought patterns and behaviours. this type of therapy was found to be as effective as ssris in most studies, i can vouch for its effectiveness.
but for help with sleep try some melatonin and some valerian.
some supps you can take now that can be taken long term to help with the anxiety are bacopa monereri and ashwagandha and perhaps some rhodiola at low doses.
aniracetam would help as would phenibut. these supps have no effect on serotonin so your good to go. dont play with you serotonin while your on paxil, trust me serotonin syndrome is not fun.
also, if you do decide to come off the paxil, make sure you wean properly, the withdrawl syndrome from paxil is BRUTAL.