Need Xpert's Help

frends,I hv Xperia Neo V,android 2.3.4 with available phone memory 420 MB.I hv moved most of the applications that I installed,to memory card.My phone is not rooted.But i noticed that the phone memory keeps on decreasing with every installation of apps on Sd card.and even if I remove the installed app,the phone memory refuses to increase. I cleared the cache etc but did not gain significant space.Can any expert help me recover phone mem without rooting.Thanks in advance