Done Serum Electrophoresis, Spike In Fast Gamma Region, Advised Zoledronic Acid. Further Steps?

I have some urgent query regarding my mother s serum electrophoresis report. She previously has a fracture in spine vertebrae D9. After biopsy of D9 vertebrae doctors found it to be a metastatic carcinoma with primary in kidney . Orthopaedics doctors suggested for kyphoplasty of D9 vertebrae which was successfully done in june 2011. A biopsy again was also done simultaeneously while operation of kyphoplasty from D9 vertebrae, reports of biopsy showed no malignancy . Blood report of Seum electrophoresis revealed M-spike 1.5 gm/dl in fast gamma region. After all that doctors advised for Radiation therapy . Which was given in 44 gray quantity on same vertebrae. Further after completion of radiation therapy given in 22 fractions. Doctor said to revisit after six weeks with report of Skeletal survey and Serum electrophoresis. Skeletal survey showed no bony lesion except cemented collapsed D9 vertebrae body. But SE report showed Mspike to be 1.55 gm\dl i.e. 0.5 greater then last diagnosis. Doctor advised to follow again after 4weeks with again report of Serum Electrophoresis and also advices a monthly injection of Zoledronic Acid . A bone marrow biopsy was also done which showed plasma cells to be 7%. After 4 weeks SE report showed Mspike to be 1.66 gm\dl. We further advised by doctor to follow after 4 weeks with same tests done. In month of December 2011 SE report showed a decrease in value of M-spike which was 1.37 gm\dl. Doctor said that its good indication and said to visit after 3 months, but also advised for injection of Zoledronic acid monthly. Now in month of March 2012 (3 months) after last visit we got SE done again and Report showed a jump in M spike to 3.02 gm\dl. Please suggest further ASAP by considering this case very important.