Hi,
If you have a lot of peppers on the plant it sounds like a chilli rather than a sweet pepper. Without knowing the variety it's hard to say but I would recommen putting out in the pot rather than planting into a bed unless you have very warm soil conditions - friends of mine plants into beds but their peppers rarely ripen. Do you know the variety?
Generall teh bigger the [pot the bigger the plant. If it's fruiting already it will be ok in the same pot but regular water and a weekly feed will be needed. I've generally found the South American varieties to be a lot hardier than the Asian.
I have been growing Chillis for several years. This year, for the first time I hardened some off in a cold frame in May and put the pots outside in the garden in June (not planted in beds). Previously I waited until July/August.
The greenhouse ones are further on but all seem quite happy, but it has been a hot summer and they are on a stone patio so presumably the heat level stays up at night. I'm in London so may have a few degrees extra.
Also planted some last weekend on the allotment where they get a lot of sun but it is very exposed. Will report on their progress if anyone's interested.