That's really all you can do...increasing your fluid intakes is usually the first step to raising your blood pressure when it's too low. Mine did that during my 2nd pregnancy as well...they would measure it and it would be like 67/35....and i felt horribly dizzy and faint and in fact passed out a few times.
Not much else they can do, although I know there are some medicines that they can sometimes prescribe I don't think they use them during pregnancy...you're less than 2 months until your due date though, so hopefully you can make it at least to full term.
best of luck! my blood pressure did return to normal after I delivered. my blood pressure is usually on the low side anyway, but it returned to about 95/68 after my son was born.
When I was in labor with my daughter they gave me Ephedrine I think to raise my bp because it was at 88/44 at the time.