Republican nominees are elected by Republican voters, in most states anyway. Your beef is with Republican voters, not the "party" as a separate entity.
If enough Republicans voted to nominate real conservative candidates, the Republican candidates who would be nominated as a result would represent conservative positions. Since that is often not true, it must be assumed that most Republican voters are not themselves as conservative as we would like them to be. The only remedy for that situation that I can think of offhand is to better educate the average Republican voter on the virtues of conservatism and how to identify a real conservative candidate.
Firstly; I would ask that you please go back and re-read my post, as you seem to have gotten some of it wrong.
Secondly; You're wrong!
Republican candidates are nominated by the most influential members of the party.
Then candidates are elected.
Furthermore, most voters are far too ignorant to know who to vote for.