ggplot2: add regression equations and R2 and adjust their positions on plot

Using df and the code below

library(dplyr) library(ggplot2) library(devtools) df <- diamonds %>% dplyr::filter(cut%in%c("Fair","Ideal")) %>% dplyr::filter(clarity%in%c("I1" , "SI2" , "SI1" , "VS2" , "VS1", "VVS2")) %>% dplyr::mutate(new_price = ifelse(cut == "Fair", price* 0.5, price * 1.1)) ggplot(df, aes(x= new_price, y= carat, color = cut))+ geom_point(alpha = 0.3)+ facet_wrap(~clarity, scales = "free_y")+ geom_smooth(method = "lm", se = F) 

I got this plot

Thanks to @kdauria's answer to this question, I added regression equations and R2 to the plot as below

source_gist("524eade46135f6348140") ggplot(df, aes(x= new_price, y= carat, color = cut))+ stat_smooth_func(geom="text",method="lm",hjust=0,parse=TRUE)+ geom_point(alpha = 0.3)+ facet_wrap(~clarity, scales = "free_y")+ geom_smooth(method = "lm", se = F) 

Now, I want to adjust the position of the regression equations and R2 to be at a specific place in each of the facets (for example at the bottom right in each facet "e.g. 0.2 y and 0.8 x).

I tried to adjust the position through vjust and hjust but it didn't work.

Any suggestions would be highly appreciated.