Using BSS84 P-channel MOSFET
I think this is the graph of your datasheet that gives all the information you need:



So assuming this circuit



V_GS is -3V which allows I_D to be up to ca. 0.5 A.

EDIT:
clabacchio is right pointing out that the graph is actually for V_DS = 5V.
Of  course a graph for V_DS = 3V would be better, but there isn't one in the datasheet.
So the question is: Will the resistance R_DSON be different for very low drain currents?
Looking at Figure 2 ("On-Resistance Variation with Drain Current and Gate Voltage") gives the answer:it does change vs. I_DS, but only for currents above ca. 0.1 A and: resistance even gets lower (=better) for lower I_DS.