You could easily calculate the confidence interval manually:
infert_control <- subset(infert$age, infert$case == 0)
# calculate needed values
m <- mean(infert_control)
s <- sd(infert_control)
n <- length(infert_control)
# calculate error for normal distribution (choose you distribution here, e.g. qt for t-distribution)
a <- 0.995 # 99% CI => 0.5% on both sides
error <- qnorm(a)*s/sqrt(n)
# calculate CI
ci_lower <- m-error
ci_upper <- m+error
See also http://en.wikipedia.org/wiki/Confidence_interval (sorry for a wikipedia link, but it has a good explanation and shows you the formula)