You'll need step down transformer, not step up, we use ~230V AC. like PC power supply, you should get higher power than the devices would draw, probably 2x or more. I got myself a
300W Automatic Transformer for a disc player that drawn ~60W.
The less than 100W version are usually comes in adapter type that plug directly to wall socket. Its convenience and less clutter not recommended as its usually cheaply made, a size this small will always have lots of corners cut.
For Audio/videophile, they usually get kilowatts rated to minimise the effect cause by the AC conversion. the higher price also allow these beast(size of AV receiver/power amp) to have better components used. Sim Lim Tower and the surrounding area all have shops selling these.
Step Down Transformer 220 110 | eBay
as for the plug, the transformer/adapter usually have universal socket. if it doesn't, get a universal plug for ~$3 from your neighbour hardware shop.
p.s. the transformer isn't expensive, the less than 100W is $20 or less; the ~300W is ~$35; the ~500W about ~$60, the 1000W is ~$100....