There are many places where one could purchase bathroom sink taps. One could check online shopping websites such as Amazon or eBay for purchasing bathroom sink taps.
A bathroom sink unit usually includes a basin / bowl and fixtures and fittings such as taps, washers drainage plug etc. One thing to note when purchasing a pack that piping is not included for plumbing the unit into the drainage.
Sink, Taps, Shower, Radiators.
aluminium
The best place to find schematic plans for sink taps would be a your local plumbing supply house. They have all the necessary diagrams and manuals.
it is made of some sort of metal
That water is used in the cold taps in your bathroom and for the heated water you use. Don't drink from these taps.
One can find sink taps at most large home improvement stores such as Home Depot and Lowes. They can also be found at big name retailers such as Walmart and Kmart.
If the taps and the spout are not connected in one unit, the spacing on your sink is probably 8 inches center to center. The only faucet I have seen for a bathroom sink with that spacing is the two handle type. There may be a single handle available. A kitchen faucet may work if the holes in the sink are large enough. Kitchen faucets are 8 inch also. If yours is 4 inch, then it is no problem, they are common.
I would hope you have your problem solved by now but the first place I would check is for a valve under the sink that is turned off. Overflowing should be a separate problem and you would check the trap under the sink.
Germophobia
Assuming you are talking about bathroom taps or washroom taps, they are used for ablution (wudhu) which is necessary before praying to Allah in Namaz, or to even touch the Holy Quran.
The American Bath Factory manufacture and sell vintage bath products and bathroom fittings. Their products include clawfoot bath tubs, whirlpool baths, shower sets, and bath and sink taps.