I haven't had one myself, but I'm a GP and used to work at Weston Park Hospital in Sheffield - one of the 3 centres in the UK which manage the results and follow-up after molar pregnancy. Being given this diagnosis is always a horrible shock, as most women aren't aware of molar pregnancies and certainly don't imagine they might have one. If you google it, I am sure you'll get the word 'cancer' in the info you find - please don't let this panic you, the vast majority of them are benign and although need to be monitored for a time, very rarely affect subsequent pregnancies (98% of women who have a molar pregnancy have normal subsequent pregnancies). Choriocarcinoma is different and requires treatment with chemo - but even with this, it is the most curable type of cancer that it is possible to get, with very good outcomes. I find it a bit bizarre that you're still waiting for a call from the hospital to be officially informed, and you've only been told 'unofficially' via your mum which sounds rather unprofessional. It does however mean that they presumably can't have any concerns about you needing treatment, or they would have contacted you as soon as they got the result.
You'll need to give a urine or blood test once a fortnight initially for bhcg levels - these will be sent to your nearest of the 3 molar pregnancy centres if you are in the UK (Charing Cross, Weston Park or Dundee) and they will monitor your levels and check they continue to fall. After the first few weeks they will monitor your levels probably 4 weekly. When they are happy that your levels are remaining low, they will advise you that it is safe to try for another pregnancy - this can take up to 12 months.
On a more personal level, my close friend had a molar pregnancy - she found the info given by the hospital fairly poor and found it a real shock to begin with, but other than the regular tests which were a bit of a nuisance, it all settled and she now has a healthy little boy from her next pregnancy.
Hope that helps a little and feel free to ring your hospital and ask them what is going on if you don't hear from them soon. I would ask to speak to the gynaecology secretaries. Sending you a hug x