I think it may be easiest to do this conversion in your own program after using readtable:
using DataFrames
#Make some canned data instead of reading from a table
df = DataFrame(datestring = ["12 Apr 1996", "05 Aug 2015"], moneystring =
["\$12.75", "\$0.69"])
df[:date] = Date()
df[:money] = 0.0
dateformat = Dates.DateFormat("dd uuu yyyy")
#map! and not map to preserve types
map!(d->DateTime(d,dateformat), df[:date], df[:datestring])
map!(x->float(lstrip(x,'$')), df[:money], df[:moneystring])
df
