One of the users mentioned Gita Press, which is a good translation. Here is the link:
Another is by Parimal Publication, Delhi. Here is the link:
Rajaji's version is an abridged one. It is good, but it skips some details for a well intended reason (to make it readable by all groups of people including a middle school kid).
Also there is an English translation by Smt. Kamala Subramaniam published by Bharatiya Vidya Bhavan.
But keep in mind that this is also an abridged version, albeit larger than Rajaji's one.
And there are many versions on the Internet like other users pointed out.