How to get rid of extra A added by Taq

[Xinyu X Song]

Hello friends,

I am doing two steps PCR mutengenesis by using homemade Taq Polymerase. 
Every time when I cloned my fragment and sequenced, I always found there 
is an extra A mismatch in the sequences which is added from the first 
step PCR  by Taq at 3' end of that strand. In my situation, there is no 
other enzyme available. Could anyone give some suggestion to get rid of 
this extra A in first step PCR? My e-mail is : xsong at uoguelph.ca.Your help 
will be really appreciated.

Thank you in advance.

Xinyu Song