1. L'Hotel Nina et Convention Centre is about 3 minutes away from Exit C3 of Tsuen Wan West metro Station. It takes about 6 minutes by west rail line from the station to Mei Foo, then it takes about 19 minutes to Admiralty, later it takes about 25 minutes by bus no. 629 from admiralty to ocean park. To Victoria Peak, you can use the same way to admiralty, and then transfer to bus no. 15 to the peak for about 30-40 minutes. To avenue of star, you can take west rial line from Tsuen Wan West to Mei foo, then transfer to tsuen wan line to TST for about 16 minutes.
2. I think it is possible to rent a taxi for 2 days in Hk, but i'm not sure about the price. I think it will be economical to book a Hk tour through a China travel company, since you need both transport and guide.