Next version of ggplot2 which is going to be 2.2.0 is bringing in a nice feature to easily add titles and footnotes. Check the sample below. You can easily load the beta version from github using this command devtools::install_github("hadley/ggplot2").

df <-
  data.frame(
    key = c("Compliance", "Information Technology"),
    budget = c(25000, 15000)
  )
  
df %>%
  ggplot() +
  geom_bar(aes(x=key, y = budget), stat = "identity") + 
  labs(x = "Department",y = "Budget in $", title = "Budget by Department", subtitle = "Budgeted Amount Distribution for XXX", caption = Sys.Date())