Welcome to Talkgraphics, if I may offer a little advice, I wouldn't buy both Xara Xtreme and CorelDraw, as they basically perform the same functions. I'd be inclined to download CorelDraw X5 as a trial as well as Xara Xtreme.
Their bitmap tracers are different and will produce different results.
I think that as you are new to graphics, you will find Xara Xtreme has the easier learning curve by far, it's also far more intuitive to use than CorelDraw.
CorelDraw does come with a bitmap editing program too - Photo-Paint, but it's more expensive than Xara Xtreme, which also handles a lot of bitmap functions well.
The money you save by not buying both - and buying the cheaper Xara Xtreme, might be better invested in buying Vector Magic: http://vectormagic.com which is widely recognised as the best of it's kind, but it's only a one-trick pony,
and an expensive one at that. If you aim to do a lot of bitmap to vector work you may find it worthwile, though.
Saludos,
Bob Taylor.