Can you let me know where you are getting stuck?...and if possible post a couple of the entries you currently have in your Degrees/Minutes column(s), if they are in a single field [eg. 1° 43' 33.4776'' S] or separately, and I'll take a look.
stab in the dark! - You only mention degrees/minutes...is the trouble that you are having that the link also adds the 'seconds' element? If so just ignore that part, as that is just an extra level of accuracy (like the number of decimal places on Long/Lat)...and if this isn't in your data you can't increase the accuracy!