Gartner Group reports that manual conversion between two similar langauges occur at the rate of about 150 lines per day. According to them, your rate of progress is just a little bit lower than average :-} Worse, it predicts you have 150 man-days of effort in front of you.
This is the reason that people build automated migration tools, that can apply conversion rules in a regular and trustworthy way. If you are lucky, somebody has done this before you. The number of pairs of from-to conversions people might want to do is huge, much larger than the set people have done, so typically you're out of luck.
The next thing somebody will tell is "use regular expressions". That probably won't work, because you have to find programmiong language constructs, which are not "regular" but rather "context free".
One way to get a tool to do this is use program transformations. These are programmed actions that replace one code fragment by another. They typically require a full language parser so that actions can operate on program elements like compilers do, rather than on text strings.
A nice way to write program transformations uses the surface syntax of the language as patterns, essentially of "if you see this, replace it by that".
Think of these as "regular expressions" beefed up to handle "context free" issues.
A tool that can accept such surface-syntax program transformations,
is the DMS Software Reengineering Toolkit.
It takes some effort to code trustworthy transformations. You have some 15,000 lines of code to convert. The tradeoff between coding the transformations vs. simply biting the bullet and doing the work is tough when the amount of code to transform is this small.