Head out to the sector space, fly to some federation transport..buy the supplies...go back to delta volanis and continue the mission (should be button on the right side of the screen). Be advised tho, that 1 medical supply costs 100 credits :-)
I remembered this from Beta, so before i left Sol i picked up 10 provisions and 10 medical supplies (wiped out my energy credits like...) just in case.
First mission i got in Delta was "We need provisions!"
Fortunate favors the bold, and apparently the prepared...