usually when medical management is selected for ectopic pregnancy HCG
level estimation should be done and then after giving the dose in 4 to 7 days if the level decreases to less than 15% of previous level it can be said that the treatment is effective.
as in your case the levels decreased to that extent possibly in few days there will be complete relief from the problem,
so wait for one more week and go for repeat ultrasound
examination meanwhile she can continue antispasmodics.
for more details you can read my article: http://srsree.blogspot.in/2012/02/ectopic-pregnancy-types-diagnosis-and.html