Having studied the abortion laws of Australia in depth it is highly unlikely that as an individual, Abbott could have any detrimental effect on the availability of abortion in this country if he was voted in. The Lib's abortion policy is rather similar to Labor's policy IMHO, so despite his religious bias I doubt he could really change legislation on the matter any more than Labor want to change it. Abbott was only able to veto the introduction of RU486 because of his role as Health Minister at the time. The simple fact is that both party's do not openly support abortion. This is why we have a legislative system where it is not legal per se but not illegal either (see section 82 and 83 of Crimes Act 1900). I highly recommend reading "Ethics and law for the health professions" by Kerridge, Lowe and Stewart which has a really objective assessment of abortion laws in this country. It is written for health professionals so it isnt too heavy on the legal jargon which is what I like about it..
I believe that women should be able to have an abortion if there are good reasons for it, but I also support regulation of the practice - and the biggest reason for regulation is the support services that are provided during the abortion process and are required by the legislative provisions.
When you actually find out what is involved in a late term abortion (google "dilation and extraction" or "partial birth abortion", but I warn you, you wont like what you read) , it makes sense to have such strict regulations, simply for the wellbeing of the woman.