Help Traveling to England in the new year!...

I Just got back from a Year in Germany and I am in Canada for xmas. Now I go back to Germany in 3 weeks and then me and my boyfriend will be driving to England to see his parents. When I drive into England they will check my passport will the stamp it and allow me to stay there for 6 months? Because after I visit with his parents I want to do some traveling. Also If they let me in for the 6months vistor time am I allowed to leave the UK say for a weekend if i want to go to another country or do I have to stay in the UK for the whole 6 months. Also do I have to prove that I have funds to support myself I read somewhere that you need 1000GBP.
Thanks in advance.