pre-seed is just a lubricant similar to something like KY Jelly but it's sperm friendly, i.e it won't kill them off or damage them like some branded lubricants do. It doesn't increase your chance of pregnancy, it simply helps to lubricate you if you don't produce enough CM or find sexual intercourse painful due to dryness etc.
On average it can take a normal couple up to a year to fall pregnant from when they first start trying properly. If you do want to concieve keep a track of your periods, changes in CM, temperatures etc and invest in an OKP (ovulation predictor) kit or monitor from somewhere like Boots or Superdrug. Most supermarkets sell the disposable OKP's, if you wanted the monitor you'd have to go somewhere like Boots.
If you haven't concieved with a year a doctor might then start doing some tests, if you went after 4 or 5 frustrated months you'd be told to return once you had been trying for 12+ months just down to the law of averages and statistics etc.
There isn't anything you can buy specifically that will aid you getting pregnant faster...if there was it would be well known and have made someone very rich indeed. Fertility drugs such as clomid are only prescribed by the GP for women who do not ovulate on a regular basis (or not at all) so even something like that isn't avaliable to the general public as most women can ovulate and produce an egg or two each month.
Good luck TTC'ing, there are no magic cures or miracle potions, sadly patience and time are, in the majority of cases, the only way to go. Just don't forget to baby dance!!