Call a lactation center. They have a guidebook that can tell you what you should take and what you can do to minimize the effects on your child.
Kellymom.com classifies it as an L3.
http://www.kellymom.com/health/meds/pain-meds.html
Says, "Aspirin use is discouraged in children and nursing mothers due to the risk of Reye's syndrome and internal bleeding." I do not know what dose this pertains to. Yours may be fine.
In the meantime, I'd pump to see if I could maintain supply. Ask your doctor what the "time being" means and if he/she has any other options for you.