I use python when using the Etabs OAPI and my code for getting all the points is:

def getAllPoints(incRestraint=False,units="mm"):
"""
This will return all the points of the model.
"""
[numberPts,ptNames,ptX,ptY,ptZ,ptCsys]=SapModel.PointObj.GetAllPoints()
#ptsConnectivityBinder=[]
#for i in range(numberPts):
# ptConnectivityBinder=SapModel.PointObj.GetConnectivity(ptNames[i])
# ptsConnectivityBinder.append(ptConnectivityBinder)
ptsRestraint=[]
if(incRestraint):
for i in range(numberPts):
ptRestraintSA=SapModel.PointObj.GetRestraint(ptNames[i])
ptRestraint=ptRestraintSA[0][0]
ptsRestraint.append(ptRestraint)
ptList=[]
for i in range(numberPts):
if(incRestraint):
if(units=="mm"):
ptList.append([ptNames[i],ptX[i],ptY[i],ptZ[i],ptsRestraint[i]])
else:
ptList.append([ptNames[i],ptX[i]*10**3,ptY[i]*10**3,ptZ[i]*10**3,ptsRestraint[i]])
else:
if(units=="mm"):
ptList.append([ptNames[i],ptX[i],ptY[i],ptZ[i]])
else:
ptList.append([ptNames[i],ptX[i]*10**3,ptY[i]*10**3,ptZ[i]*10**3])
return ptList

Thanks for your response.
But this will give me all the points in the model. I want data only for the selected points(the points which user selects in the model).

Yup, I get all the points in a list like in the code above, then the code would be something like:

selectedPts=[]
for i in ptLst:
if SapModel.PointObj.GetSelected(i)==True:
selectedPts+=[i]