If you are simply using qPCR with SYBR Green to determine relative expression levels, you don't need any special software.  Excel will do just fine.  Set up your spreadsheet to calculate the delta CT for each sample by subtracting the CT of reference gene (e.g. actin, cyclophilin etc.) from the CT of your gene of interest.  (Usually samples are analyzed in duplicate or triplicate so calculate the average CT values for each sample first.)  Then set a column to calculate the delta delta CT for each sample by subtracting the delta CT for your control sample from the delta CT for each experimental sample.  Finally, relative expression is determined by the following formula:  2 exponent negative ΔΔCT, which is expressed in Excel using the circumflex symbol to denote the exponent, as  2^-(∆∆CT).  The control sample will have an expression of 1 (because ∆∆CT = 0) and the experimental samples will be calculated relative to the control.

Try LineRegPCR. It may work.

Usually leftech machines have their own software to analyze the data, you just need to download it.