You’re right when you say that $|\Bbb N|=\aleph_0$, but $|\Bbb R|$ is $2^{\aleph_0}$, often abbreviated to $\mathfrak{c}$, which may or may not be $\aleph_1$. The statement that $|\Bbb R|=\aleph_1$ is the so-called continuum hypothesis, often abbreviated to $\mathsf{CH}$; it’s known that the usual axioms of set theory do not imply that $\mathsf{CH}$ is true and also do not imply that it is false (assuming, as we do, that those axioms are themselves consistent). The great majority of mathematicians do not assume that $\mathsf{CH}$ is true.
Yes, there are larger cardinalities. Cantor’s theorem says that if $A$ is any set, $\wp(A)$, the set of all subsets of $A$, has larger cardinality than $A$. In particular, $\wp(\Bbb R)$, the set of all subsets of $\Bbb R$, has cardinality larger than $|\Bbb R|$; its cardinality is $2^{\mathfrak{c}}=2^{2^{\aleph_0}}$. The set of all sets of subsets of $\Bbb R$, written $\wp\big(\wp(\Bbb R)\big)$, is bigger yet: its cardinality is
$$\huge 2^{2^{\mathfrak{c}}}=2^{2^{2^{\aleph_0}}}\;.$$